Crosman Air Pistol Owners Forum

Crosman air pistol - General => Crosman air pistol - General discussion => Topic started by: quickster47 † on March 25, 2013, 03:59:47 PM

Title: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 03:59:47 PM
So which is better, the OEM bolt probe, a shaped extended bolt probe, a small diameter rod extended bolt probe, a flow through bolt probe, or a probeless bolt design?  This question gets asked over and over, and again and again on our forum and many others.  And while this is a pretty exhaustive test it will probably never be answered to suit everyone.  But that's okay.  If you do the same tests your results might vary from what mine showed.  Perhaps that is just the nature of the airgun beast.

I tried to be as consistent as I possibly could with my testing so as not to taint the results.  But I will tell you this right up front, I am so sick and tired of taking this gun apart that it will take me a month or more to recover, I think. :)

To start with I built up a basic 2240 gun but used a Crosman Custom Shop non stamped tube and a 1701P trigger frame.  Everything else is plain Jane 2240 stuff including the plastic breech and the front barrel band.

I used three different chronometers but finally settled on using a cb-625 chronoscope version 2 for all the final testing.  While some may pooh-pooh this let me say that as long as you don't mix apples and oranges it doesn't matter which one you use.  Just use the same one for consistency.  Another thing was for me and this testing it was all about convenience.  Mainly because I sat in the kitchen with the sliding door open and the screen door on the back covered deck wide open so I could shoot into the woods.

For the first test I wanted to characterize the 2240 so I fired 240 pellets and used eight powerlets.  I would fire 30 pellets and then change the powerlet.  I used the same pellets for all my testing, JSB Diabolo Exacts weighing in at 14.3 grams.

I will begin posting the resultant data throughout the day and evening as I have time.

Carl
Title: Re: Five Easy Probes
Post by: droid on March 25, 2013, 04:05:40 PM
I'm looking forward to this Carl, I have never been convinced that the probes make a major difference. So you will settle the argument with this for me.
Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 04:09:10 PM
I'm looking forward to this Carl, I have never been convinced that the probes make a major difference. So you will settle the argument with this for me.

You will be surprised at the results and what ends up being the best probe as far as increased FPS.  I know I was.   :)

Carl
Title: Re: Five Easy Probes
Post by: droid on March 25, 2013, 04:11:14 PM
To be honest Carl, I was under the impression that the standard bolt can outperform some of the so called "upgrade" ones, so I will wait and see.
Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 04:23:56 PM
So the first results I will show are the average of those 240 pellets fired in batches of 30 pellets at a time.  This gun is not a hot shooter and I really suspect it is in the middle of the production bell curve.  Some will be better and some will be worse.

This is the OEM bolt/probe in brass as it come from Crosman.  Nothing done except a tiny drop of Pellgun oil on the o-ring.

Carl

Title: Re: Five Easy Probes
Post by: Tater on March 25, 2013, 04:26:58 PM
Cool tests, can't wait to see the results.
Title: Re: Five Easy Probes
Post by: crossliner on March 25, 2013, 05:14:07 PM
Cool tests, can't wait to see the results.

Same here  8)
Title: Re: Five Easy Probes
Post by: airguns100 on March 25, 2013, 05:19:50 PM
Nice test, Carl. I'm really glad your doing this. Super interested in finding out what you find here.
I'm going to guess, and say second from the left in the photos "extended skinny probe" might allow for greater flow. I can't wait to see.  :)
Title: Re: Five Easy Probes
Post by: breakfastchef on March 25, 2013, 05:20:45 PM
I am leaning toward your choice.

Nice test, Carl. I'm really glad your doing this. Super interested in finding out what you find here.
I'm going to guess, and say second from the left in the photos "extended skinny probe" might allow for greater flow. I can't wait to see.  :)
Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 05:37:16 PM
The second results are from the average of 240 pellets fired in batches of 30 pellets at a time using the shaped brass extended probe.  Again the only thing done was a tiny drop of Pellgun oil to the o-ring.  I also changed the powerlet after each 30 shots.

Carl
Title: Re: Five Easy Probes
Post by: droid on March 25, 2013, 05:39:20 PM
Well I was wrong already. Good difference on just these two  :-*
Title: Re: Five Easy Probes
Post by: HappyHunter on March 25, 2013, 06:02:31 PM
Thanks for taking the time and doing all the legwork on this, Carl :-* I'll be keeping an eye on this one for sure!

I'm going to guess, and say second from the left in the photos "extended skinny probe" might allow for greater flow.

That is my guess too. Hope it's right seeing as that is the one I use in all my guns!  :o

Todd
Title: Re: Five Easy Probes
Post by: Cross Pistol Packer on March 25, 2013, 06:26:07 PM
The results of the flow through bolt I will be most interested to see Carl.
Fitted to my 2260,it leaves little room to load a pellet,if I dont have a good power increase over stock bolt its history.
Title: Re: Five Easy Probes
Post by: KevinP on March 25, 2013, 06:44:54 PM
Awesome test so far ...   :-*
Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 06:52:42 PM
Here are the results from the third test.  These are the average of 240 pellets fired in batches of 30 pellets at a time using my homemade extended probe made from a piece of 0.081 stainless rod.  Again the only thing done was a tiny drop of Pellgun oil to the o-ring and also a change of the powerlet after each 30 shots.  I tried to make this probe the same length as the brass probe to keep the testing consistent although I'm not too sure it makes much of a difference once the pellet is seated in the rifling past the transfer port.

Carl


Title: Re: Five Easy Probes
Post by: droid on March 25, 2013, 07:08:04 PM
That one surprised me, shouldn't that one have hindered the airflow ? Sorta defeats the point of a hollow probe now doesn't it ? Or does it ?
Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 07:27:27 PM
Here are results from the fourth test.  These are the average of 240 pellets fired in batches of 30 pellets at a time using the Charles Mellon flow-through probe that I cleaned up ever so slightly to remove some tiny burrs.  Not that I am prejudice but this has always been my go-to probe for all my target guns.  Again the only thing done was a tiny drop of Pellgun oil to the o-ring and also a change of the powerlet after 30 shots.

The length of this probe is slightly shorter than the other two extended probes but I believe it has a more consistent seating of different pellet types if you are prone to changing pellets quite often. Although for this test I have used the same pellet type throughout my testing.  You can also see from the first picture that the opening is directly over the transfer port and lined up very well with the transfer port.

Carl
Title: Re: Five Easy Probes
Post by: ped on March 25, 2013, 09:03:35 PM
great data carl :-* good job you weren't using a pumper or you'd have arms like arnie :D
i normally use hollow probes not because they give better fps gains than the extended probes but i found that they load pellets better with less chance of the pellet cockling
i have just made an extended one with a wider tip that seems to work well for loading once past the breech screw hole(once i'm happy with the gun i think a little filler will be going in)
ped
Title: Re: Five Easy Probes
Post by: droid on March 25, 2013, 09:06:16 PM
I just thought, I hope no one is hiding in the woods  ;D
Title: Re: Five Easy Probes
Post by: WyoMan on March 25, 2013, 09:27:30 PM
Well performed test Carl.....the results seem logical to me and I'm with you on the points you make  :-*
Glad you did this because the probe thing was almost an urban legend......now we need someone to do an accuracy test  ;D
Title: Re: Five Easy Probes
Post by: arkmaker on March 25, 2013, 09:52:39 PM
So that leaves the solid probe  :)
Title: Re: Five Easy Probes
Post by: ped on March 25, 2013, 10:17:51 PM
i wonder if thats going to give a suprise result
ped
Title: Re: Five Easy Probes
Post by: BigErn on March 25, 2013, 11:20:18 PM
Very cool stuff Carl! Thank you for sharing this great info  :-*
Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 11:34:16 PM
Here are results from the fifth and final test.  These are the average of 240 pellets fired in batches of 30 pellets at a time using my very own designed probeless bolt.  This was quite a challenge to test because it was very, very easy to load up a pellet and shoot the gun before realizing I had not removed the filler probe.  I ended up having to make at least eight of these probeless blanks because of mishaps.   :D  Again the only thing done was a tiny drop of Pellgun oil to the o-ring and also a change of the powerlet after 30 shots.

This one was the biggest surprise of all the tests.  I certainly did not expect even the slightest gain and because of some previous testing I actually expected a loss of FPS.  The filler pieces were made about 0.190" in length and the one end was concave to mate better with the bolt end, not that doing that made any difference in the testing but it did make me feel better. :)

Carl

Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 11:37:02 PM
And the data from the probless bolt tests.

Carl

Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 11:40:03 PM
So what does all this mean?

I think the one thing that crosses my mind about the last two tests, the extended flow-through bolt and the probeless bolt, is that was my barrel getting well seasoned after a thousand shots and did that make any difference or are these type of bolt probes actually better.  From a realistic standpoint you can really throw out using a probeless bolt because of its impractability.  It just ain't gonna happen in the real world.  Although I suppose one could make use of it in some type of shooting competition.  But you would definitely need to be well disciplined.

And does such a small increase in FPS really make any difference in the big scheme of things.  Sometimes I believe it does then at other times I think not.  Others have done some similar tests but I don't believe anyone has done anything quite like what I did.

This testing was a lot like the barrel testing I did in October 2011.  It was a lot of fun and a whole lot of work but after shooting 1200 pellets and going through 40 powerlets I am really, really glad it is finished for the time being.

Carl
Title: Re: Five Easy Probes
Post by: breakfastchef on March 25, 2013, 11:41:45 PM
No way! I wonder if reducing the headspace in the cavity behind the pellet with that 'oil drum' you concocted may actually be beneficial. Just guessing.

Your tests prove that most any bolt that pushes the pellet past the transfer port increases pellet velocity.
Title: Re: Five Easy Probes
Post by: quickster47 † on March 25, 2013, 11:48:26 PM
No way! I wonder if reducing the headspace in the cavity behind the pellet with that 'oil drum' you concocted may actually be beneficial. Just guessing.

Your tests prove that most any bolt that pushes the pellet past the transfer port increases pellet velocity.

What I would do is insert a pellet, close the bolt, pull the bolt back, insert the 'oil can', close the bolt and fully seat the pellet, pull the bolt back, remove the oil can, close the bolt and fire.  Whew...  and the problem was that sometimes I would forget to pull the bolt back and remove that 'oil can'.  :-[

And I think that is pretty much true, any bolt pushing the pellet past the transfer port is a winner.

Carl
Title: Re: Five Easy Probes
Post by: breakfastchef on March 25, 2013, 11:53:40 PM
So let me clarify this...the oil can was removed after setting the pellet? Or it is an integral part of the bolt that remains in place during the firing sequence?

What I would do is insert a pellet, close the bolt, pull the bolt back, insert the 'oil can', close the bolt and fully seat the pellet, pull the bolt back, remove the oil can, close the bolt and fire.  Whew...  and the problem was that sometimes I would forget to pull the bolt back and remove that 'oil can'.  :-[

And I think that is pretty much true, any bolt pushing the pellet past the transfer port is a winner.

Carl
Title: Re: Five Easy Probes
Post by: arkmaker on March 25, 2013, 11:53:42 PM
OK, wait!! Let me make sure I have this correct. You use the probeless bolt, add the drum, add the pellet and lock it in, then open and remove the drum and re-lock and fire??


Is that right??
Rich
Title: Re: Five Easy Probes
Post by: breakfastchef on March 26, 2013, 12:20:08 AM
Who'd have thunk it. This being the case, the lack of any object in the path of the airflow provided the highest fps. Kind of make sense.

OK, wait!! Let me make sure I have this correct. You use the probeless bolt, add the drum, add the pellet and lock it in, then open and remove the drum and re-lock and fire??


Is that right??
Rich
Title: Re: Five Easy Probes
Post by: mrb02334 on March 26, 2013, 12:27:26 AM
Carl, you have done some great work. I personly would like to thank you for the time and expense that you spent on this project.
So how long berore your one piece oil can bolts are aviable? I don't need a bolt handle, I have a screw driver that will fit in the hole!
Thanks again for your work.
Jon
Title: Re: Five Easy Probes
Post by: ped on March 26, 2013, 12:46:06 AM
when i first got my as2250 i read about extended probes well not having one and being brought up with  mend or make do mentallity and being pretty resourceful i used to seat the pellet further into the barrel with an allen key i'd cut down
now wether this brought any gains i don't know because i didn't have a chrono at the time ,i then got a gmac hollow probe and haven't used this method since
might have to try this again
ped
Title: Re: Five Easy Probes
Post by: eric on March 26, 2013, 01:16:54 AM
excellent work carl --- was there any variation in temps between those tests  ??
Title: Re: Five Easy Probes
Post by: quickster47 † on March 26, 2013, 01:17:25 AM
So let me clarify this...the oil can was removed after setting the pellet? Or it is an integral part of the bolt that remains in place during the firing sequence?

Quote
OK, wait!! Let me make sure I have this correct. You use the probeless bolt, add the drum, add the pellet and lock it in, then open and remove the drum and re-lock and fire??

Is that right??
Rich

The 'oil can' is removed after seating the pellet.  The 'oil can' is not part of the probe, it is only used to push the pellet past the transfer port into the rifling and then removed.

The bolt is then closed again to seal off the transfer port and the entire air path to the rear of the pellet is clear.

Carl
Title: Re: Five Easy Probes
Post by: quickster47 † on March 26, 2013, 01:20:47 AM
excellent work carl --- was there any variation in temps between those tests  ??

All the shooting was actually done from inside the house with the sliding back door open to the outside about 12".  Outside temperatures varied from 39 to 50 degress over the fours days of shooting/testing.  Temperature inside was 68 degrees.

No rain any shooting days and three of those days was sunny, but cool.

Carl
Title: Re: Five Easy Probes
Post by: Brent on March 26, 2013, 01:25:05 AM
Just got a chance to see this. Very Cool!! Thanks Carl!!  :-*

It so does make sense that with nothing at all in front of the pellet, that would perform the best. Never thought that far on it, but it so makes sense (just talking out loud... I know and realize you guys are already there. GOOD idea to try that Carl!).

I always thought the smallest diameter extended probe possible, like the wire probe, would do the best... If only by virtue of less air resistance. That does not necessarily play out here by much, but I am still leaning that way... and the last test seems to support that.

The thoughts/ thinking on a hollow probe versus an extended probe, being very much about the same... are proven here some more. That is good to finally know for sure!

There are thoughts that at higher pressures the hollow probe wins out. Hummm

So after stating the obvious (sorry guys... just glad I finally got to see for sure)... I am grateful for all the time and expense spent on this! "Thanks Carl"

Title: Re: Five Easy Probes
Post by: airguns100 on March 26, 2013, 01:26:04 AM
Yeah, i was wondering what the large round probe -oil can- was. So basically not having any probe proved more flow. I guess the next test would be what probe produces the most accuracy.   :P
I currently use D.C's SS tear drop shaped probes, and i'm going to assume it flows similar to the brass extended probe.

Great work, carl. I'm glad some one finally did that.  :-*
Title: Re: Five Easy Probes
Post by: arkmaker on March 26, 2013, 01:31:55 AM
Thanks Carl!! That was an awesome time consuming test for you.


You should sticky this thread  :-*  It is worthy of "Stickiness". People are going to keep asking about probes for a long, long time to come.


Rich
Title: Re: Five Easy Probes
Post by: Brent on March 26, 2013, 01:38:27 AM
Thanks Carl!! That was an awesome time consuming test for you.


You should sticky this thread  :-*  It is worthy of "Stickiness". People are going to keep asking about probes for a long, long time to come.


Rich

Yep... So true.

So let's go from here....
What do we use as the very smallest diameter, strongest wire possible... that we can drill out the end of our stock bolts for, and mount into them? I am really not sure?
Title: Re: Five Easy Probes
Post by: quickster47 † on March 26, 2013, 01:43:28 AM
Good idea Rich simply because it does get asked over and over.

And as mentioned, the best probe appears to be one that just puts the pellet in front of the transfer port.

However, with that thought still in the air and looking at the results of the probeless (disappearing 'oil can' probe) bolt, I am getting an idea for a new fangled bolt that might just be a winner.

Carl
Title: Re: Five Easy Probes
Post by: arkmaker on March 26, 2013, 01:47:40 AM
All in all, I still like the hollow tip probe for the fact that it seems to make loading easier for me. I'll give up a few fps for the theory that the skirt gets pushed in square. Knowing that I am only a few fps off helps re-enforce my preference for it. Cause, I am not patient enough to remove the oil drum each time!!



Title: Re: Five Easy Probes
Post by: quickster47 † on March 26, 2013, 01:53:15 AM
Yep... So true.

So let's go from here....
What do we use as the very smallest diameter, strongest wire possible... that we can drill out the end of our stock bolts for, and mount into them? I am really not sure?

For my extended probe I used some 0.081" stainless steel wire.  That size was probably the largest size that could be used safely without collapsing the inner walls of the o-ring groove.

I'm sure you could use some 0.0625" (1/16") stainless wire and get away with that size too.

Perhaps someone has already used a smaller size and will chime in here.

Carl
Title: Re: Five Easy Probes
Post by: Brent on March 26, 2013, 01:59:26 AM
All in all, I still like the hollow tip probe for the fact that it seems to make loading easier for me. I'll give up a few fps for the theory that the skirt gets pushed in square. Knowing that I am only a few fps off helps re-enforce my preference for it. Cause, I am not patient enough to remove the oil drum each time!!

That's a really good point Rich! A square pellet would seem to shoot more accurately with the pressure hitting it evenly!

I am so not sure in asking this... for discussion by those that know better than me - but if we used something small in diameter to push the pellet in past the transfer port... does the lead in of the barrel up into the rifling... allow for the pellet to become, and/ or load not square at that point?

Can't wait to see your "new fangled bolt" design Carl!!  :-*
Title: Re: Five Easy Probes
Post by: targettgii on March 26, 2013, 02:06:15 AM
That must have been very tedious work Carl thank you very much for your hard work.
Title: Re: Five Easy Probes
Post by: WyoMan on March 26, 2013, 02:12:48 AM
That was a cool idea with the probeless setup....maybe an original  8)
What I find interesting about the physics part is that improving the flow more than trumps the offsetting loss in parasitic transfer volume..
which is the dead space that the pressurized air fills in between the valve and pellet......so,
a really hollowed out flow thru is a good bet in 22 cal....thanks again Carl  :-*
Title: Re: Five Easy Probes
Post by: Brent on March 26, 2013, 02:30:48 AM
That was a cool idea with the probeless setup....maybe an original  8)
What I find interesting about the physics part is that improving the flow more than trumps the offsetting loss in parasitic transfer volume..
which is the dead space that the pressurized air fills in between the valve and pellet......so,
a really hollowed out flow thru is a good bet in 22 cal....thanks again Carl  :-*

Wyo... you understand this more than I - so would you think a hollow probe with really thin sides walls, but the smaller inside diameter thus still... versus an extended probe with a really small diameter wire, but in that possibly causing turbulence in the air (co2) as the air tries to move around it still - is better?

I am not sure there is a right or wrong answer here guys  ???
But Carl has gotten us this far... so let's see if we talk it out, just maybe we will all together figure out the ultimate bolt once and for all... if there is one  ??? :-*
Title: Re: Five Easy Probes
Post by: 1377x on March 26, 2013, 02:35:14 AM
Wyo... you understand this more than I - so would you think a hollow probe with really thin sides walls, but the smaller inside diameter thus still... versus an extended probe with a really small diameter wire, but in that possibly causing turbulence in the air (co2) as the air tries to move around it still - is better?

I am not sure there is a right or wrong answer here guys  ???
But Carl has gotten us this far... so let's see if we talk it out, just maybe we will all together figure out the ultimate bolt once and for all... if there is one  ??? :-*

airforce guns use the ultimate set up
the air come from directly behind the pellet.no turns bends loop d loops
Title: Re: Five Easy Probes
Post by: DaveB50 on March 26, 2013, 02:35:27 AM
Thanks for doing this Carl, great review of bolt designs. How long before someone makes a bolt with a retractable probe? A bolt within a bolt?
Dave
Title: Re: Five Easy Probes
Post by: AgentWD40_FL on March 26, 2013, 02:40:58 AM
Nicely done Carl.  :-*
Title: Re: Five Easy Probes
Post by: WyoMan on March 26, 2013, 02:54:53 AM
Wyo... you understand this more than I - so would you think a hollow probe with really thin sides walls, but the smaller inside diameter thus still... versus an extended probe with a really small diameter wire, but in that possibly causing turbulence in the air (co2) as the air tries to move around it still - is better?

I am not sure there is a right or wrong answer here guys  ???
But Carl has gotten us this far... so let's see if we talk it out, just maybe we will all together figure out the ultimate bolt once and for all... if there is one  ??? :-*

Not sure which (flow thru or extended probe) can provide better flow, you maybe right about turbulence  ??? with the probeless giving
the best results......tells me the gas likes flow.....
Title: Re: Five Easy Probes
Post by: arkmaker on March 26, 2013, 03:08:09 AM
I am so not sure in asking this... for discussion by those that know better than me - but if we used something small in diameter to push the pellet in past the transfer port... does the lead in of the barrel up into the rifling... allow for the pellet to become, and/ or load not square at that point?


Yes, the lead in helps no doubt, but think of the head of the pellet. Ya know how when you put a pellet in the breech and it tilts down nose first and then gets hung up in the stupid screw counter-bore. Well using the  hollow tip probe seems to help that a bit and should keep the pellet held in place all the way to its final resting place.
My theory is that if using just a straight tipped probe the pellet could be pushed into the barrel tilted all the way to its final resting place, distorting the skirt.


Now, does that actually happen? Who knows for sure. I would like to make a plexiglass barrel and see for sure.
Anyway, there is my twisted train of thought.
Rich
Title: Re: Five Easy Probes
Post by: cheewee on March 26, 2013, 04:01:38 AM
Thanks for doing this Carl, great review of bolt designs. How long before someone makes a bolt with a retractable probe? A bolt within a bolt?
Dave

i actually looked into this but after testing on a probeless bolt i had very eratic fps readings and decided against it. maybe time to rethink it.
Title: Re: Five Easy Probes
Post by: cheewee on March 26, 2013, 04:54:10 AM
Thanks for doing this Carl, great review of bolt designs. How long before someone makes a bolt with a retractable probe? A bolt within a bolt?
Dave
actually thought about doing this but after testing on a probless bolt decided against it because of very eratic fps reading
Title: Re: Five Easy Probes
Post by: ettolo on March 26, 2013, 08:15:05 AM
Thanks for doing this Carl, great review of bolt designs. How long before someone makes a bolt with a retractable probe? A bolt within a bolt?
Dave
i figured the same thing!  :D
Title: Re: Five Easy Probes
Post by: arkmaker on March 26, 2013, 09:25:40 AM
Something spring loaded, so that the probe would retract automatically when you lock the bolt and extend when unlocked!


Not asking for much, am I?
Title: Re: Five Easy Probes
Post by: Cross Pistol Packer on March 26, 2013, 10:18:02 AM
Nice work :)
Title: Re: Five Easy Probes
Post by: dptrucker32chip on March 26, 2013, 12:47:25 PM
Good job  Carl .  :-* :-* :-*  Good information  !!!  Thank  u ,for all ur hard work . :-* :-* :-*
Title: Re: Five Easy Probes
Post by: quickster47 † on March 26, 2013, 01:41:34 PM
How long before someone makes a bolt with a retractable probe? A bolt within a bolt?
Dave

This is what I have been contemplating since I finished the testing.  It would definitely be a design challenge but there are lots of us out there that like a good challenge.

Carl
Title: Re: Five Easy Probes
Post by: crossliner on March 26, 2013, 01:53:12 PM
Kind of like a telescopic probe but that is too much hard work on too small a part. Then there is the issue of air going to waste. Or it can be done the syringe way. You know a long thin rigid shaft (w/ some kind of a stopper) that impales the breech plug as well the bolt..Kind of like a mini power adjuster  ???
Title: Re: Five Easy Probes
Post by: JEBert on March 26, 2013, 09:45:10 PM
It would be much easier to design a bolt with an end that just directed the air to the front without regard to placing the pellet.  Then have a hand-held probe that would push the pellet in, perpendicular to the bolt to a point just ahead of the transfer port.   You wouldn't need to close the bolt on it, just have it the right shape to fit into the chamber and length to push the pellet to the right place while the bolt is open. The hand-held piece might have to be held to the gun with a lanyard to keep from losing it.
Cheers,
Title: Re: Five Easy Probes
Post by: ped on March 26, 2013, 10:41:42 PM
i used to use an old allen key(hex driver) cut down to so that it  pushed the pellet past the port i then got a hollow probe and never used this method(i didn't have a chrono so i never new how well this worked)
ped
Title: Re: Five Easy Probes
Post by: JEBert on March 27, 2013, 04:12:06 AM
Quote
i didn't have a chrono so i never new how well this worked
How was the accuracy?
Title: Re: Five Easy Probes
Post by: BerkshireHunter on April 14, 2013, 04:00:04 AM
Just stumbled on this, great testing. Never thought the different probes would make that much difference. (And I thought a stock 2240 was closer to 450 fps) Each gun's different.   :-*
Title: Re: Five Easy Probes
Post by: quickster47 † on April 14, 2013, 04:08:09 AM
Each gun can be very different.  Also, Crosman advertises the 2240 as "Up to 460 fps" but they never ever list the actual pellet and pellet weight they use to achieve that velocity.  Heck, with a Prometheus alloy pellet I can get 550 fps but it won't have much stopping power because the pellet is so light.

Carl
Title: Re: Five Easy Probes
Post by: Cwlongshot on April 28, 2013, 03:01:03 PM
Just stumbled on this, great testing. Never thought the different probes would make that much difference. (And I thought a stock 2240 was closer to 450 fps) Each gun's different.   :-*

Same here!!  I have been searching the web for this kind of info. Very nice to find it right here at home!  Yesterday I modified my own probe on my '77. I was going to remove the factory brass .010 beyond the O ring. But after drilling decided to just thin it to give support for the steel probe. BUT all I really needed to do was drill deeper for that support.   :o :o

I have picked up a couple more probes and will mod one for my 2240 too.  :P :P

I agree it would be a crying shame if this post was not stickied!!

THANK YOU SO MUCH for all the effort and expense providing this information for all who follow!!!  :-* :-* :-* :-* :-*
Title: Re: Five Easy Probes
Post by: Colt25 on May 29, 2013, 06:27:58 PM
Both my 13xx guns have OEM bolts that I have filed down the probe on a lathe.

~5 fps increase. It's laughable.
Title: Re: Five Easy Probes
Post by: splat on July 10, 2013, 05:53:22 PM
Just found this, VERY interesting and thanks for all your work.
It seems to me that the perfect answer would be for someone at Crosman to design a gun where the bolt is the valve/gas store.
pull bolt back and it connects at rear to accept a charge of gas, push forward and lock. then bolt contains one shot worth of gas.
No transfer port to snag, no directing gas through two 90 degree turns to get it behind pellet.
lol who knows one day they may make the perfect gun (probably the day before they become obsolete in favour of laser blasters).
again thank you. ATB.
Title: Re: Five Easy Probes
Post by: arkmaker on July 29, 2013, 11:15:35 PM
Just found this, VERY interesting and thanks for all your work.
It seems to me that the perfect answer would be for someone at Crosman to design a gun where the bolt is the valve/gas store.
pull bolt back and it connects at rear to accept a charge of gas, push forward and lock. then bolt contains one shot worth of gas.
No transfer port to snag, no directing gas through two 90 degree turns to get it behind pellet.
lol who knows one day they may make the perfect gun (probably the day before they become obsolete in favour of laser blasters).
again thank you. ATB.


That would be an Air Force gun...... also would take all the fun out of modding these bad boys!!  ;)
Title: Re: Five Easy Probes
Post by: Gipper49 on October 13, 2013, 06:02:23 PM
I realize I am kinda late to this party but how about a 2 prong fork type probe?  The 2 prongs would be perpindicular to the breech when loading then parallel(sp?) when loaded.  Or think of it as a slotted flow through bolt.  Then you could taper the slot for best flow.
If that still doesnt make sense make a Peace sign and then flatten your wrist.

Brian
Title: Re: Five Easy Probes
Post by: quickster47 † on October 14, 2013, 01:41:46 AM
Brian that sounds like an interesting idea.  Make me one and I'll do some free testing for you.  :)

Carl
Title: Re: Five Easy Probes
Post by: The Robin on October 17, 2013, 01:30:32 PM
Just been reading through this thread as a newbie, very interesting reading and also great work on the testing  :-*
Title: Re: Five Easy Probes
Post by: sshewins on November 05, 2013, 04:31:32 AM
Hey Carl, thinking in terms of cavitation of airflow, how does this idea sound. A hollow probe, BUT, instead of just drilling  it per se, use a round dremmel type bit and only going as far as necessary to meet up with the port opening. Basically, like porting and polishing on a hot rod engine.

My minds eye has a perfectly smooth air pathway.  Take more work to do, but perhaps the benefits would be similar to your oil can set up, and slightly more practical.
Title: Re: Five Easy Probes
Post by: arkmaker on November 05, 2013, 10:31:49 AM
Hey Carl, thinking in terms of cavitation of airflow, how does this idea sound. A hollow probe, BUT, instead of just drilling  it per se, use a round dremmel type bit and only going as far as necessary to meet up with the port opening. Basically, like porting and polishing on a hot rod engine.

My minds eye has a perfectly smooth air pathway.  Take more work to do, but perhaps the benefits would be similar to your oil can set up, and slightly more practical.


I like it :-*
Title: Re: Five Easy Probes
Post by: quickster47 † on November 05, 2013, 01:25:33 PM
Hey Carl, thinking in terms of cavitation of airflow, how does this idea sound. A hollow probe, BUT, instead of just drilling  it per se, use a round dremmel type bit and only going as far as necessary to meet up with the port opening. Basically, like porting and polishing on a hot rod engine.

My minds eye has a perfectly smooth air pathway.  Take more work to do, but perhaps the benefits would be similar to your oil can set up, and slightly more practical.

I like that idea also.  Will give it some serious thought.

Carl
Title: Re: Five Easy Probes
Post by: sshewins on November 06, 2013, 05:21:56 PM
Ok, just had me another thought. Why re-invent the wheel. If you have an extra hollow probe lying around,  fill the drill intersection with some epoxy and reshape it.

All this is based on never having seen a hollow probe, just assuming that it is made by drilling two holes and calling it a day.

I don't know, maybe I'm over-thinking it.
Title: Re: Five Easy Probes
Post by: arkmaker on November 06, 2013, 08:37:36 PM
I don't know, maybe I'm over-thinking it.


Nahh........That's half the fun!!  :-*
Title: Re: Five Easy Probes
Post by: KevinP on November 06, 2013, 09:22:30 PM

Nahh........That's half the fun!!  :-*

So true ....  if it doesn't work, try it again ... and again ..... and again .....
Title: Re: Five Easy Probes
Post by: arkmaker on November 07, 2013, 01:53:19 AM
Yep, but my probe experimentation has run its course for a little bit ;)
Title: Re: Five Easy Probes
Post by: BDS on November 08, 2013, 07:34:00 PM
Yep, but my probe experimentation has run its course for a little bit ;)

 :D ...That's what SHE said!  ;D  :-*
Title: Re: Five Easy Probes
Post by: quickster47 † on November 08, 2013, 07:46:44 PM
^^^ Now those last two posts are exceedingly funny.  ;D

Carl
Title: Re: Five Easy Probes
Post by: KevinP on January 30, 2014, 11:32:04 AM
I just reread this post ... again thanks Carl ....  :-*
Title: Re: Five Easy Probes
Post by: BDS on January 30, 2014, 05:10:28 PM
Always interesting to review (some) of the old threads, also interesting to see the one, or two time visitor/members (at least 6 guys in this thread) who went away never to return?
Title: Re: Five Easy Probes
Post by: quickster47 † on January 30, 2014, 06:07:38 PM
Always interesting to review (some) of the old threads, also interesting to see the one, or two time visitor/members (at least 6 guys in this thread) who went away never to return?

You are so correct Brian.  I just went back and reviewed the thread to see how many folks have disappeared.  Amazing.

Carl
Title: Re: Five Easy Probes
Post by: BDS on January 30, 2014, 08:29:15 PM
I am "correct"?  Ya... once in awhile.

I think many of those guys are here for a quick "mod-my-gun for me" visit.

Do you think we have 50 hardcore members? Maybe fewer?
Title: Re: Five Easy Probes
Post by: ped on January 30, 2014, 09:45:16 PM
the uk crosman forum suffers this new members (not all) seem to have a problem ask a few questions get some advice then are never heard of again unfortunately thats how the world is
ped
Title: Re: Five Easy Probes
Post by: sshewins on February 01, 2014, 04:10:01 PM
I'm still around. I just don't post unless I have something semi-intelligent to add. Or something possibly funny.   :-*
Title: Re: Five Easy Probes
Post by: quickster47 † on February 02, 2014, 12:46:48 AM
I'm still around. I just don't post unless I have something semi-intelligent to add. Or something possibly funny.   :-*

I like that.  :-* :-* :-*

Carl
Title: Re: Five Easy Probes
Post by: MavStone on February 02, 2014, 04:24:16 PM


I need to find me a forum without so much chatter!

You guys talk too much....  ;D

Title: Re: Five Easy Probes
Post by: Paul55 on February 02, 2014, 05:18:46 PM
What a great read, thanks for all your hard work in this.  I have an idea, no idea if it's feasible though & no metal working tools or skills to find out, but here goes.  Could you make a solid probe, the same length as a hollow probe the drill out the centre to make a tube.  Then instead of drilling a hole, remove the bottom section of the probe.  I envision the probe looking  a bit like a train tunnel.  Does that make any sense?  If the rear of the hollow tube part was curved forward would this also help gas flow?  An awful description I know but hopefully you'll get what I mean  :-[
Title: Re: Five Easy Probes
Post by: Adam77K on February 02, 2014, 06:33:33 PM
Like a horseshoe in cross-section Paul?  Sounds like a good idea if it was rigid enough.
Though I'm not sure what the gains would be over a hollow probe with a large enough aperture at the bottom and nice smooth porting inside.
Title: Re: Five Easy Probes
Post by: Paul55 on February 02, 2014, 06:37:16 PM
That's was I was thinking  :-*  My thinking was that there would be more free space for the gas.
Title: Re: Five Easy Probes
Post by: sshewins on February 03, 2014, 11:55:08 PM
My concern would be the flow if air, or turbulence. But the patent pending "no bolt bolt" sorta alleviates my concern with that. So I'd have to guess that it would probably be ok from that standpoint.
Title: Re: Five Easy Probes
Post by: johnf1966 on February 12, 2014, 11:36:42 AM
Very  good tests and thanks for taking the time to  produce all the data, very interesting.  I have an extended hollow probe in a gmac steel breech and am seriously considering taking it out.  The FPS is better as proven here but I find it can pinch  the skirt on the pellet and can also damage the head.  As the probe is pushing the pellet forward of the breech port the pellet head drops slightly into  the breechport and can  damage it. I use domed pellets, it does not work well with flatheads.  A damaged pellet will affect its aerodynamics on its way  to  the target.
Title: Re: Five Easy Probes
Post by: quickster47 † on February 12, 2014, 02:49:32 PM
johnf1966 what you say is quite true. I find that when making and using an extended probe it is best to make it work with one particular pellet and try and stay with that pellet in that gun.  Which these days is easy to do.

Carl
Title: Re: Five Easy Probes
Post by: johnf1966 on February 13, 2014, 10:45:11 AM
Thanks Carl.
 :-*
Title: Re: Five Easy Probes
Post by: Xxoo0o0o0ooxX on April 04, 2014, 03:01:18 AM
Here are results from the fourth test.  These are the average of 240 pellets fired in batches of 30 pellets at a time using the Charles Mellon flow-through probe that I cleaned up ever so slightly to remove some tiny burrs.  Not that I am prejudice but this has always been my go-to probe for all my target guns.  Again the only thing done was a tiny drop of Pellgun oil to the o-ring and also a change of the powerlet after 30 shots.

The length of this probe is slightly shorter than the other two extended probes but I believe it has a more consistent seating of different pellet types if you are prone to changing pellets quite often. Although for this test I have used the same pellet type throughout my testing.  You can also see from the first picture that the opening is directly over the transfer port and lined up very well with the transfer port.

Carl
I love the flow-through probe for 2240's  :-\ Does anyone know if they are made for the P-rod pistol?
Title: Re: Five Easy Probes
Post by: quickster47 † on April 04, 2014, 02:42:58 PM
I love the flow-through probe for 2240's  :-\ Does anyone know if they are made for the P-rod pistol?

Not sure if there are any being made for the P-rod but will look around.

Carl
Title: Re: Five Easy Probes
Post by: South Bay Dave on June 06, 2014, 07:57:37 AM
Carl, thanks for the work you put into this and the cool data presentation.  Your findings were most helpful in my understanding of the head space past the valve.
 I had only one thought that seemed untouched by the earlier discussions that I may try here at home if I can find the means.  I would make the wire probe as you did and then taper down the midsection of the probe between the tip and the o-ring and finish the tip in an enlarged round (skinny in the middle, wide at the ends and rounded on the face) -sort of a tear drop looking thing if you were holding the probe pointed down.   My thinking is that this would allow more of the air to collect behind the pellet and then be further increased in pressure as it moves past the widened tip of the probe thus compensating for the suspected turbulence issue - however, because this would be constricting on the air flow I don't know if there would make a positive difference.

Happy Plinking!


Dave
Title: Re: Five Easy Probes
Post by: WaltWhite on July 08, 2014, 07:12:58 AM
Lots of great information here!  Does anyone know how applicable this information is for a 1377-type gun?

If I've extrapolated correctly from these seven pages, would it be best to stick with a stock bolt if you plan to run a variety of pellets?
Title: Re: Five Easy Probes
Post by: quickster47 † on July 08, 2014, 02:44:39 PM
Lots of great information here!  Does anyone know how applicable this information is for a 1377-type gun?

If I've extrapolated correctly from these seven pages, would it be best to stick with a stock bolt if you plan to run a variety of pellets?

You can still use a custom probe with a variety of pellets and the loss of efficiency will most likely be very negligible.  So my suggestion is get yourself an extended probe and use it.

Carl
Title: Re: Five Easy Probes
Post by: sshewins on July 10, 2014, 12:13:29 AM
Johnf, have you tried melting some wax on the breech screw? Ooze a little Crayola on the screw and form it a little. Should keep your pellets from hanging up and getting damaged. Plus, you can remove it later, if necessary.
Title: Re: Five Easy Probes
Post by: Poorman Plinker on August 10, 2015, 04:53:47 PM
Granted that the test was about velocity and not accuracy and the tests were done very professionally and the results presented very scientifically. Thank you Carl. . 8)
Title: Re: Five Easy Probes
Post by: arkmaker on August 11, 2015, 06:09:21 PM
Glad to see someone thinking about this again.


Another train of thought to ponder is when Carl and I talked about using a bolt that filled the bore of the barrel, pushing the pellet past the transfer port, which would only make contact with the back of the skirt, but then retracting while still leaving a seal on the ramp of the bore. This would leave the entire camber open, seal and do the least amount of damage to the pellet by limiting tilt that can accompany an extended bolt probe. Nothing really has been done on this because frankly it would be a PIA to make and the pay off just isn't there (for most folks).


Personally, I do favor extended bolt probes over hollows just because they are easier to make. That said, I would not trade the Hollow bolt that is on my 114 for anything. Even then, for the minimal gain that requires $ and/or time, the stock bolts can't be faulted to awful much. My 1740 uses a stock bolt and I have had great results and a fairly flat shot string.


Anyway, keep thinking and pretty soon you will be consumed with the 22xx/13xx platforms and on the verge of bankruptcy like the rest of us  ;D
BTW: Welcome to the Forum!
Title: Re: Five Easy Probes
Post by: Poorman Plinker on August 12, 2015, 02:30:37 PM
LOL Arkmaker... I may be new to this forum, but already way over my head in Crosman parts and spending way too much time on the topic. Thanks for the welcome and the thought provoking ideas.  8)
Title: Re: Five Easy Probes
Post by: quickster47 † on August 18, 2015, 03:39:20 AM
Actually, I still have my plans for a probeless bolt that could be made with some expert time in a machine shop.  I talked to some students at Tennessee Tech and we were looking at other ideas.  And then I was in contact with some of my old physics profs at Purdue but nothing came out of that.  Seems they were more interested in being retired like I was.  :D

Anyway, there are some other things on my plate and I may get back to all that one day real soon now in the near distant future.  :P

Carl

BTW, I still shoot my box stock 2240 more than any other airgun and must say I love it more and more.  But then I do have some of my other modded guns and they are still awesome too.
Title: Re: Five Easy Probes
Post by: Poorman Plinker on August 18, 2015, 04:03:54 PM
I just saw a movie that centered around the "safety needle". This is a type of syringe that pushes into the skin and then retracts automatically. The movie was about the drama of distribution and monopoly and did not address the technology. However that might be the technology you are looking for. I too might be retired, but this is now my retirement pastime LOL 8)
Title: Re: Five Easy Probes
Post by: Paul on February 08, 2016, 07:25:57 AM
Thank you for taking the time to do this extensive test.
As a result I have ordered the extended probe with the hole in it,
can't wait to do some testing of my own.
Title: Re: Five Easy Probes
Post by: CraigH on March 03, 2016, 10:05:20 PM
More great testing and information - I can hardly keep up.   8^)

I have been looking at the various bolt probe arrangements and thinking as to how they all operate, so this comes at an excellent time just as I am ready to order.

I'm not going to repeat all the information I have seen here on CAPO and elsewhere as to all the + /- of the two major styles, except to mention depth of seating with extended probes due to depth of skirt hollow, and skirt pinching with hollow probes.

So, I am thinking the best arrangement would be the hollow probe, but ever so slightly reduced in diameter and with a perhaps 45 degree relief on its end.  That hopefully to eliminate skirt pinching and perhaps even help seat the skirt itself to the chamber / barrel.

Title: Re: Five Easy Probes
Post by: quickster47 † on March 03, 2016, 10:55:52 PM
Craig,

If you were always, forever and ever, going to use the exact same pellet in your gun then it would be easy to design an extended probe or hollow probe for the pellet.  Problem is we switch pellets quite often so we sort of need a probe that works with all pellets.  And that would be an extended hollow probe.  Properly designed it is your best choice.

Carl
Title: Re: Five Easy Probes
Post by: CraigH on March 03, 2016, 11:03:18 PM
Thank you, Carl!

That is what I thought would be the answer.

Your tests are VERY enlightening!
Title: Re: Five Easy Probes
Post by: Rualert on March 08, 2016, 04:14:24 AM
     Hey guys, so I'm really late this party, but great job Carl, and thanks for the data and info. Here's a though on the retractable bolt, take a page from Bob's (RSterne) book of knowledge. How about first we see if we have enough room in a standard steel or aluminum breech for a short slot back just low enough to allow the bolt to rotate down and have a lock. This slot could then be adjusted back until the front of the solid probe clears the transfer port. This may require a slightly taller breech, as I have seen it done that way but generally tall breeches that would also allow a full shroud to me added. I'm thinking stock height or maybe just a small amount taller fro those that don't want a tall breech. All of these design ideas would require I believe an o-ring groove in the back of the breech to seal the probe, thus removing the need for it on the actual probe.

Casey

P.S. Hey Ark, maybe something you have the tooling to prototype once you get caught back up. Don't remember if you have a mill Carl.
P.S.S. I may try slotting one of my stock breeches, just have to find the time.
Title: Re: Five Easy Probes
Post by: quickster47 † on March 08, 2016, 04:30:10 AM
     Hey guys, so I'm really late this party, but great job Carl, and thanks for the data and info. Here's a though on the retractable bolt, take a page from Bob's (RSterne) book of knowledge. How about first we see if we have enough room in a standard steel or aluminum breech for a short slot back just low enough to allow the bolt to rotate down and have a lock. This slot could then be adjusted back until the front of the solid probe clears the transfer port. This may require a slightly taller breech, as I have seen it done that way but generally tall breeches that would also allow a full shroud to me added. I'm thinking stock height or maybe just a small amount taller fro those that don't want a tall breech. All of these design ideas would require I believe an o-ring groove in the back of the breech to seal the probe, thus removing the need for it on the actual probe.

Casey

P.S. Hey Ark, maybe something you have the tooling to prototype once you get caught back up. Don't remember if you have a mill Carl.
P.S.S. I may try slotting one of my stock breeches, just have to find the time.

Casey,

That's a great idea.  I have plenty of spare breechs in various configurations that can be made sacrificial lambs for this endeavor..  Also have a small mill so I'll see what I can turn up/out.

Carl
Title: Re: Five Easy Probes
Post by: CraigH on March 08, 2016, 05:30:28 AM
Casely,

Great idea and remarkably simple concept.   :-*  It may be that the breech would only require a vertical latch farther back than the original latching point.  That is, push the pellet forward, then pull the bolt back to the new vertical latch point.  (If I hear the general concept correctly)

Carl,

The oil can (or was it tin can) returns!
Title: Re: Five Easy Probes
Post by: quickster47 † on March 08, 2016, 01:48:20 PM
Casely,

Great idea and remarkably simple concept.   :-*  It may be that the breech would only require a vertical latch farther back than the original latching point.  That is, push the pellet forward, then pull the bolt back to the new vertical latch point.  (If I hear the general concept correctly)

Carl,

The oil can (or was it tin can) returns!

Another great idea.  Hopefully I will be able to try out one or both of these ideas later this week.  Adding another latch point may be the best approach as I was looking at a Crosman steel breech this morning and there is not a whole lot of room.  But time will show us.

Craig it could have been the can-can.   ???  :D

Carl
Title: Re: Five Easy Probes
Post by: CraigH on March 08, 2016, 02:02:31 PM
Yes, space is very limited.  For a horizontal slot and even another latch point.  Looking at the breech and bolt, which will have to be new for the enlarged probe, the bolt handle will probably need to be moved rearward on a factory steel breech.  The locking slot that Casey (not Casely  :-[) presented would be elegant, but I cannot see enough space, at least on a breech already machined by Crosman.
Title: Re: Five Easy Probes
Post by: oldgearhead on March 08, 2016, 02:04:54 PM
Cool idea. ???
Title: Re: Five Easy Probes
Post by: quickster47 † on March 08, 2016, 02:21:59 PM
Here's one to ponder on while I make a trip to the dentist this morning.

Carl
Title: Re: Five Easy Probes
Post by: oldgearhead on March 08, 2016, 02:46:19 PM
Yes! The answer is in the slot, not the bolt...but sealing might be more difficult, or require a different leade design/size]  :-*
Title: Re: Five Easy Probes
Post by: CraigH on March 08, 2016, 04:03:47 PM
Carl,

If that breech and bolt are already fitted, about all that is needed is a properly located o-ring groove.  Definitely a hefty piece.  I would say around twice the weight (in steel) of a Crosman steel breech.

A very nice piece upon which to ponder.
Title: Re: Five Easy Probes
Post by: Paul on March 08, 2016, 08:52:40 PM
From Caliber to calcium, looking good, I'll watch this one.
Title: Re: Five Easy Probes
Post by: twigboy on March 09, 2016, 12:57:29 AM
Yes! The answer is in the slot, not the bolt...but sealing might be more difficult, or require a different leade design/size]  :-*

Put the o-ring (or 2) in the receiver?   ???  Slightly taper the bolt so that it glides through without catching the o-ring(s)
Title: Re: Five Easy Probes
Post by: Rualert on March 09, 2016, 01:41:20 AM
   Yes Craig, I like that idea, and I mis-spoke on the placement of the o-ring, back of the barrel cut an o-ring groove, like the M-Rod, and a few others. This allows the bolt to push the pellet into the barrel, past the transfer port, pulled back then locked. I think we may have collectively stumbled on a potential design. The taller breech would be easier to implement, but a standard design type with the top slot log enough to push the pellet into the chamber, pull back, then lock down rather than the lock down at the front. This may very well work, see we are all smarter together.  :)  :-*

Casey

P.S. Yes Carl, that design of the taller breech gives the room for the J type slot, and I'm sure you read Bob's post where he added a small SHCS to limit the reward travel of the bolt after lowering it into the j slot to adjust how much of the TP is covered to adjust the amount of air getting to the back of the pellet or slug.
Title: Re: Five Easy Probes
Post by: Rualert on March 09, 2016, 02:39:45 AM
    OK, had to throw in one more idea here, this might be better in the machining section if so please move there. Now to the point, someone mentioned a chamber behind the pellet for the charge/air expansion. This got me thinking about the TAU Junior I repaired for the state 4-H club. Their design is based around a bulk fill but also uses 12 gram carts. The cart is inserted in the grip tip down rather than up, and the cap pierces it and allows the gas to fill the space around the cart, and another space above it where their valve is located. Kinda hard to explain without pictures, but anyway the valve allows the gas to then flow into an expansion chamber just below the breech area. Pellets load directly into the barrel by hand (no probe or bolt), when the hammer opens the valve the gas fills that expansion chamber and is directed to the back of the pellet. I'll see if I can fin a decent picture. Collectively we might be able to design a breech that could be used with say a Pro Top that mimic's the expansion chamber design and only uses the bolt to seal the chamber so the gas gets directly to the back of the loaded pellet. OK, off to find a decent picture of their design so the group can ponder and think about the potential of such a breech / bolt design to implement such a design.

Casey
Wow crazy what one can think up once we have a grasp on Crosman's design and other's designs and trying to come up with a hybrid.

Found the exploded diagram of the Tau, might help show what I was trying to describe:

(http://s5.postimg.org/oemgysnc7/tau7ex.jpg) (http://postimage.org/)
screenshot software (http://postimage.org/app.php)
Title: Re: Five Easy Probes
Post by: CraigH on March 09, 2016, 02:57:46 AM
Casey,

Years and years ago (squared) this is kind of the way I though the various Crosman CO2 air guns worked; i.e., the air tube was pressurized and pressing the trigger shot the gas from another valve-controlled chamber through the bolt.
Title: Re: Five Easy Probes
Post by: quickster47 † on March 09, 2016, 03:01:55 AM
Casey, wow a TAU.  Can't believe that.  I've had one of those for 15 years and still have it and still shoot it.  Awesome, accurate gun for sure.

Carl

Okay, way off track, sort of.  But now we return control to the real thread.  :)
Title: Re: Five Easy Probes
Post by: Flattitude on March 09, 2016, 09:11:43 PM
Wow beautiful gun.
Title: Re: Five Easy Probes
Post by: Rualert on March 18, 2016, 01:20:06 AM
     They are very nice, I maintain most if not all of the air guns for the state 4-H program when they have more than simple issues. But as you said back to the point, if we were to add the o-ring to the end of the breech to seal the probe, then the solid or tubular probe could be a little simpler, along with the option of a pull back slot or second drop down slot to use after seating the pellet.

Just thinking out  loud again,

Casey
Title: Re: Five Easy Probes
Post by: mudduck48 on March 18, 2016, 01:21:34 AM
You had better watch that thinking out loud, you know that gets you in trouble. ;D
Title: Re: Five Easy Probes
Post by: quickster47 † on March 18, 2016, 02:10:48 AM
     They are very nice, I maintain most if not all of the air guns for the state 4-H program when they have more than simple issues. But as you said back to the point, if we were to add the o-ring to the end of the breech to seal the probe, then the solid or tubular probe could be a little simpler, along with the option of a pull back slot or second drop down slot to use after seating the pellet.

Just thinking out  loud again,

Casey

And I keep thinking and thinking about this probeless bolt.  Going over all kinds of ideas in my head and making notes and sketches.

One of these days, one of these days...

Carl
Title: Re: Five Easy Probes
Post by: mudduck48 on March 18, 2016, 02:38:48 AM
Probeless bolt? ???
Title: Re: Five Easy Probes
Post by: quickster47 † on March 18, 2016, 02:54:09 AM
Close but no cigar.  That bolt still has a large appendage that blocks the transfer port, even if it is a flow through bolt.

Carl
Title: Re: Five Easy Probes
Post by: Poorman Plinker on April 03, 2016, 03:17:35 PM
 :-* I think Rualert has a good point. (Not being a machinest I will never build one) I agree that if the o-ring is not on the probe there IS more room/flexability for building a retractable bolt .
Apart from that, I have observed: In a hand loaded gun you need only press the pellet a bit deeper to make an expansion chamber.
My rhetorical/theoretical question is: Is it the expansion of the gas that caused the increased velocity or is it the gas hitting the full face (skirt) of the pellets?
Pressing a pellet a bit deeper into a Single Stroke pneumatic and doing some Chronograph tests might shed some light on the subject. Maybe using a TAU?
Carl, this post is going to go down as a classic in the pellet gun hall of fame and I reference it frequently. 8) Thanks for doing the research.
Title: Re: Five Easy Probes
Post by: quickster47 † on April 03, 2016, 03:22:07 PM
I am currently working on an extended tip probe that has an adjustable extension.

Pictures later and maybe some test data when I get a few things off my plate.

And even though I'm retired there still is not enough hours in the day.   ???  :D

Carl
Title: Re: Five Easy Probes
Post by: Poorman Plinker on April 03, 2016, 03:35:26 PM
Here's one to ponder on while I make a trip to the dentist this morning.

Carl
Missed this before commenting... Stroke of genius Carl! So simple to just have the bolt lug allow the bolt to retract. That should work perfectly regardless of pellet design and requires no complicated mechanisms. O-ring or seal in the breech trapped between the breech and barrel face? "The Quickster Probe-less Breech" - fits any standard 22xx Crosman receiver and barrel.
Title: Re: Five Easy Probes
Post by: CraigH on April 03, 2016, 04:09:21 PM
Quote
And even though I'm retired there still is not enough hours in the day.

Especially if one is an inefficiency expert like me.   ;)

I've had this topic on hold in my mind, but the little lathe is supposed to arrive tomorrow and there will be an overload of competing ideas on various subjects.  On this topic I can only see a sealing of the breech a bit back of the barrel.  It could be on the solid probe or on the bolt body and of course a breech body machined to work as such.

I still like the two-latch breech to keep its height down as the "J" slot requires a taller breech (not necessarily a problem).

Carl,

I am sure you will have an elegant solution and look forward to seeing it.
Title: Re: Five Easy Probes
Post by: arkmaker on April 03, 2016, 05:26:21 PM
And then I think it was mentioned somewhere in this thread, that the 1950's hollow porbes were brass. The seal end was round and the handle was located on a taper. Thus, the harder you lock the bolt, the tighter the seal on the barrel. Never had a bit of leakage at the seal point on my 114 and I never used much force at all. This year makes that rifle 60 years old  :-*
Title: Re: Five Easy Probes
Post by: CraigH on April 03, 2016, 06:16:48 PM
Rich,

Do you (or can you) make that tapered bolt latch point on your breeches?
Title: Re: Five Easy Probes
Post by: ped on April 03, 2016, 08:12:09 PM
it's real easy to make the retracting probe work
first you need to use an o ring in the barrel like a p-rod but the o ring is in a counter bore so it becomes trapped by the rear of the breech bore (imagine a p-rod barrel that has had the back machined off to the groove)
for the probe you use one with a solid end that will seal in the o ring  and clear the bore ,the retracting part is that you use a straight pull bolt with a spring loaded handle that drops into a counter bore slot in the breech slot
where the counter bore slot is determin's how much the bolt retracts
this one is set up for a std probe but to make it retractable all I need to do is mill the counter bore back towards the rear of the breech so the bolt handle drops in the slot and carries on forwards seating the pellet ,then you pull it back till it hits the back ff the counter bore slot 
Title: Re: Five Easy Probes
Post by: arkmaker on April 03, 2016, 11:33:41 PM
Rich,

Do you (or can you) make that tapered bolt latch point on your breeches?

Guess I could, but no plans to do it. Seems the standard waycrosman does this now works.
BTW the 114 has a rear pull  bolt !ikethe mrod (similar)
Title: Re: Five Easy Probes
Post by: Pumpmeister on April 06, 2016, 01:00:35 PM
Ca

     I Would favor the  first 3 ,beginning (from left..flow-thru being favorite)  I think they'd get the
Air(or Co2) to Pellet better & faster than OEM ...IMHO

Mario
Title: Re: Five Easy Probes
Post by: Rualert on April 14, 2016, 01:14:21 AM
    Nice looking breech there Ped. Damn it now I really need the parts to make the milling adapter for my lathe. Money, money, money. Hey if the guns don't eat it up all the tooling to try, research, test, prototype and create these parts will eat up ones wallet. Guess the upside is once you make something unique, it's yours until someone copies it. But hey what's the saying about it being the greatest form of flattery? Hum, I wonder if I could drill a stop in the side of my standard breech, then make the solid extended probe, that could then be retracted after loading like what Ped describes. So many projects, o little time.

Casey
Title: Re: Five Easy Probes
Post by: CraigH on April 14, 2016, 01:22:07 AM
Casey,

Depending on the size of your lathe, milling is frequently difficult and not so successful.
Title: Re: Five Easy Probes
Post by: Poorman Plinker on May 07, 2016, 09:56:31 PM
That is a nice action/breech you built there Ped. I think the Quickster reversing bolt handle groove might be a bit easier to build than the counter bore design... You probably saw it on Crosman Poorman Mods where the bolt goes into the trapped o-ring like you have and then the handle drops and pulls back (making a U turn) leaving the "chamber" empty and the pellet forward of the port.
Title: Re: Five Easy Probes
Post by: ped on May 08, 2016, 10:20:07 AM
I've seen a few of Bob sterne's breech's that use the J bolt idea
Title: Re: Five Easy Probes
Post by: Kilmister on May 29, 2017, 04:20:47 PM
I think I would have liked Quickster, for those of you who were close to him you have my sincere condolences. Its funny I should bump into this article though as I have been obsessing lately over this very topic. Reading through it and all of you hashing it out for some time reminds me of the concept of original thoughts and there not being any left ;D Would have loved to have been able to meet this Gentleman and see his findings but that's just not always the cards we get dealt (his hand, not mine yet). So here is my pledge to a man I never knew, I am already theoretically well down the path, once I get my shop finished (real soon, less than a week or two tops) I am going to follow this through to it's conclusion and I have a couple things of my own to add as well!
Cheers, Kilmister
If this bothers anyone who was close to him I am sorry. However; I have been obsessing over this and a closely related concept for a awhile now. It has been a forgone conclusion that I was going to immerse myself in finding the best way to get the most air behind an undamaged pellet skirt for some time, this gives me someone to dedicate that work to!
Cheers, Kilmister aka Martin
Title: Re: Five Easy Probes
Post by: Tater on May 30, 2017, 07:39:06 AM
I didn't know him personally, just what a great guy he was through his postings here, his actions, and what others here have said. It was ALL good.
I think it's great that you will carrying his great thoughts and ideas forward. Best of luck, looking forward to your results.
Title: Re: Five Easy Probes
Post by: JEBert on June 09, 2017, 04:33:08 AM
I was not fortunate enough to meet Carl face-to-face but from our conversations and his posting/sharing here, I think that if he were still around that he would tell you to take any info he posted and use it any way you see fit, and please post your results.

Carl was as generous as anyone I've met.  I miss him.

Many blessings,
Jerry
Title: Re: Five Easy Probes
Post by: Noah on June 09, 2017, 09:29:38 AM
I was not fortunate enough to meet Carl face-to-face but from our conversations and his posting/sharing here, I think that if he were still around that he would tell you to take any info he posted and use it any way you see fit, and please post your results.

Carl was as generous as anyone I've met.  I miss him.

Many blessings,
Jerry

X2  :-*
Title: Re: Five Easy Probes
Post by: CraigH on June 09, 2017, 01:10:13 PM
Martin,

I am sure Carl would like continuing progress.   This "Five Easy Probes" has always been my favorite series.

He is greatly missed.
Title: Re: Five Easy Probes
Post by: TraderJoe on August 08, 2017, 05:43:04 PM
Disclaimer: I am neither an engineer, a physicist, nor machinist. I also am not a "mod maniac" (a compliment to those of you who are  :-*). I have read every one of these posts and am truly impressed with the knowledge of all those who have contributed! Here is my bottom line question. I have a CCS 2240 (.22 cal) on order and from my understanding of what I've read is that one of the the simple mods I should do to improve performance is to replace the stock probe with a flow thru or extended probe. Also planning on a power adjuster. I will initially be shooting the 10' barrel but anticipate going to the LW 14.6 barrel. Thanks in advance for your comments. (http://crosman-air-pistol-owners-forum.com/pics/Brutuz/tnxm8.gif)
Title: Re: Five Easy Probes
Post by: CraigH on August 08, 2017, 11:16:45 PM
A return of my favorite project on CAPOF!   It is the reason I use the Mellon flow-through probe/bolt - sometimes "tuned" a bit.   Carl did excellent work on this!   
Title: Re: Five Easy Probes
Post by: Poorman Plinker on August 09, 2017, 07:29:30 PM
Hi Trader Joe,
IMHO Carl did a great job on the research and longer probes not only increase velocity but increase standard deviation as well. Maybe not enough to affect close range accuracy. The hollow probes have a reputation of deforming the skirts as well (probably not all probes and not all skirts).

I have extended probes in most of my Crosman. I buy the Disco probes direct from them. I also use Disco striker springs (heavier gauge) that are cut short to reduce hammer bounce and save gas and reduce the standard deviation of shot velocity. But that is just me... does not work well for everyone.

The longer the barrel the more gas you can use... too much hammer or flow with short barrels is often a waste of shot count that produces very little overall efficiency (cumulative FPE divided by the number of shots within a % of FPS drop). But math is not for everybody either LOL.
 8)
Title: Re: Five Easy Probes
Post by: TraderJoe on August 11, 2017, 12:07:20 AM
Well I guess at some point the length of the barrel falls under the "Law of Diminishing Returns"
Title: Re: Five Easy Probes
Post by: Nvreloader on August 24, 2017, 06:00:50 AM
Just finished reading all of these posts, thoughts and info given etc, given by Carl and everyone else.
Outstanding test of these probes,   :-*
I am interested in the hollow flow thru probe, for the upcoming mads to my QB 79, 22 caliber rifle.

Has anyone followed up with any more test results?

RIP Carl, you have earned it....as your actions have proven, beyond any shadow of doubt.  :(

Tia,
Don
Title: Re: Five Easy Probes
Post by: Termite on February 20, 2019, 03:47:02 PM
I'm a relatively new member and just read this entire Post.  The exhaustive work that Carl did is simply amazing.  I wish I'd had the chance to get to know Carl.  From reading this post I can tell he was a great guy!
Title: Re: Five Easy Probes
Post by: CraigH on February 20, 2019, 04:17:27 PM
Terminte,

Thanks for bringing this topic to the forefront.   Your comments, all true, are appreciated.    :) :( :)