Last time I had my 2400kt out it wasn't puncturing the Co2 cartridge like it had usually been doing. It was barely making a hole in the tip of the cart. Since then I have been finishing off my 2289, currently building a 1377 and bought a 2240 so I haven't messed with the 2400kt at all. Thinking this weekend ill get it out and shoot it but wanted to hear your thoughts on the problem. I believe I had read somewhere that if you have your trigger over travel screw set too close to the trigger where it stops it right as it fires, it puts drag on the seer and doesn't "hit" as hard. In turn, not puncturing the cart enough. If i remember correctly, i think i was messing with that after the first few times i took it out to shoot. Anyone else have any experience with this or can elaborate? This is where I'll probably start with my troubleshooting to see if it was the culprit, if not maybe its time to order parts from Crosman..
I have had that exact thing happen with a trigger over-travel screw adjusted too close on a 1377. It would only dump 6 pumps worth of air in the valve until I backed-off of the over-travel screw a little more. The drag was causing too light of a hit from the hammer to dump all of the air with more than 6 pumps in it. I expect that on a Co2 gun the problem would have been too light of a hit on the cart.
I think I had to back it off at least 1/2 turn after the sear released to dump 10 pumps of air (factory piston and valve).
As always, your mileage may vary.
Cheers,
Thanks Jerry. I thought I had heard before that it could cause a problem if the over travel screw is tightened too much but wasn't sure. With hearing that you experienced the same problem I'm betting that backing off the screw a little bit may fix my problem. Should get some shooting time this weekend to find out. Thanks for the info.
I have a couple of 2300S pistols with the old style triggerframe and it still escapes me to understand how not permitting the trigger to go farther than the point of releasing the sear HOLDS THE SEAR AGAINST the hammer. If you look at the levers involved nothing can hold the sear lever against the hammer other than the spring/assembly which doesn't directly connect to the trigger blade. Once the sear is released it will drag against the hammer with the force of the sear spring ONLY, the trigger blade NEVER exerts an upward force on the sear lever.
Carl
I really don't understand it myself, seems like it wouldn't matter as long as the sear releases from the hammer ???. That'a another reason that I asked was to see if you guys had heard of this before and if so, could help me understand a little bit better of what is causing it to happen. I could see having the grip frame side panel shimmed and tightened too much could cause a problem also. Kind of weird tho if it is the trigger over travel screw.. I'm not gonna do anything else to the gun besides loosen the screw and ill report back if it helped.
take out the cart and have a look at the seal on the valve, my bet is it is squished not letting the cart to be pierced. This is apparently pretty common because of tightening the cap like a man not a little girl like it should be...
I've yet to experience this annoying problem with my 2300KT pistol, or 2400KT carbine, but I have had it happen with my Tech Force 78 rifle which utilizes two 12 gram cartridges.
Quote from: rangerfredbob on May 17, 2013, 03:18:28 PM
take out the cart and have a look at the seal on the valve, my bet is it is squished not letting the cart to be pierced. This is apparently pretty common because of tightening the cap like a man not a little girl like it should be...
Ill have a look at that if backing the screw off doesn't work. I try not to hulk the Co2 cap on there when I tighten it but may have tightened it a little too much one of the last few times I put a new cart in.
I think that because the front of the hammer is rounded a little, it releases just a little bit before the sear completely clears it. with the over-travel setscrew limiting the trigger from moving the sear to fully clear the hammer, the sear spring causes the sear to drag against the bottom of the hammer as it passes.
Just my thoughts,
Quote from: JEBert on May 17, 2013, 05:06:58 PM
I think that because the front of the hammer is rounded a little, it releases just a little bit before the sear completely clears it. with the over-travel setscrew limiting the trigger from moving the sear to fully clear the hammer, the sear spring causes the sear to drag against the bottom of the hammer as it passes.
Just my thoughts,
Makes sense.. :-*
Quote from: JEBert on May 17, 2013, 05:06:58 PM
I think that because the front of the hammer is rounded a little, it releases just a little bit before the sear completely clears it. with the over-travel setscrew limiting the trigger from moving the sear to fully clear the hammer, the sear spring causes the sear to drag against the bottom of the hammer as it passes.
Just my thoughts,
x2. When the over-travel screw is set in too far, it prevents the trigger from going backwards enough to fully push the sear down and away from the hammer. This condition not only can mess with the cartridge puncture, but can also reduce velocity and provide higher than normal shot counts.
Quote from: breakfastchef on May 17, 2013, 05:41:30 PM
x2. When the over-travel screw is set in too far, it prevents the trigger from going backwards enough to fully push the sear down and away from the hammer. This condition not only can mess with the cartridge puncture, but can also reduce velocity and provide higher than normal shot counts.
The reduced velocity that you mentioned is probably also the reason why I was hitting low on the target and had to re zero my scope the last time I had it out.
First time I have ever heard this. Makes sense though. Thanks Larry! :-*
Need to check mine now... I like them set fairly close.
Found out today that after backing the over travel screw out a little bit, it was putting nice clean holes in the cart again. Was also shooting a lot better than the last time I had it out. Thanks for all the input on this subject.
Great. Nice little tidbit of info to know.
Big hole, little hole? Does it matter? Since we are talking gas, once it escapes the cart and settled in the valve, I would think the size of the hole it came from would make no difference.
Just me thinking ???
Rich
Quote from: arkmaker on May 23, 2013, 01:16:09 PM
Big hole, little hole? Does it matter? Since we are talking gas, once it escapes the cart and settled in the valve, I would think the size of the hole it came from would make no difference.
Just me thinking ???
Rich
I would agree with that Rich but does it fill the valve slower with a small hole, just me trying to think.
Mike
Quote from: Crosshairs on May 23, 2013, 01:22:06 PM
I would agree with that Rich but does it fill the valve slower with a small hole, just me trying to think.
Mike
Doesn't fill the valve any slower because it's under pressure and the shot is using gas already in the reservoir.
The 22xx valve does double duty as it acts as both a reservoir and a gateway between the powerlet and the transfer port, and ultimately the barrel with a pellet in the chamber. The firing process is activated by the hammer striking the valve stem assembly which opens the reservoir portion of the valve to allow the metered charge of gas in the chamber to escape out the transfer port and ultimately propel the pellet.
On the other end of this arrangement is the piercing pin which will only at the limit of its travel, when the valve is fully open, close the hole in the cap of the powerlet. The entire rest of the time as the valve is opening and closing gas is both flowing out of the valve into the transfer port and barrel, while at the same time gas is dumping out of the powerlet into the valve. When the valve re-seals it finishes refilling from the powerlet to prepare for the next shot.
Carl
I would think just like any liquid it would move slower with a smaller hole I know it turns to a gas but that only happens when it hits the air so you would think the small hole less volume. ???
I suppose it is possible to only puncture the powerlet cap and create a micro hole and that could inhibit flow. You would also notice that immediately because you would have essentially no velocity to speak of.
Not sure how small is too small. Something to investigate one of these dark and stormy winter nights in the near distant future. :)
Carl
This is one of those times that I would like to pick the brain of the engineer that designed the 22xx valve.
Is the valve system designed to dump gas only from the valve (from tip of cart to TP) or is it designed to dump gas from the valve body and also added gas from the cart? If the latter were true, then I think a larger hole will make a difference. If not, then I do not think the hole size makes much difference, since we are taking the reaction of a liquid turning to gas and the flow of that gas would be pretty quick, I would think.
In my thinking (and I am no expert), but in my thinking, I would design the valve to hold a certain amount of gas and then for each shot to expel only that amount of gas only. This way FPS/FPE would be controlled and consistent for the life of the cart. It is accomplished by use of a known hammer weight and known hammer/valve spring and known TP opening size along with known caliber, which allows the gas to escape through the TP for a pre-determined known time. That time is calculated from the consistency of the know factors of hammer weight, spring tension and TP/barrel opening size. To me, that is the only way to determine a consistent shot to shot FPS/FPE.
If anything, I would want to have enough gas available in the valve, so that once the time factor has expired (valve stem closes) there would be a tiny bit of gas left from the starting amount, which would then be replaced from the cart for the next shot.
Of course this is talking of a stock gun. Bulk filling and modding the valve for performance brings on a whole new set of factors. Which is why we experiment with Boss Valves, TP size, grinding valve stems, polishing internals, heavier and lighter springs, etc.....
Again, just thinking and typing. Does any of it make sense? Who knows, but like I said, I sure would like to talk to the original designer and hear first hand how he thought it should all work.
Rich
All true but remember it's the the liquid going through the hole not the gas so if that's true then a small hole would let less liquid out. ???
This is a good one for picking our brains.
Mike
Quote from: Crosshairs on May 23, 2013, 02:11:24 PM
All true but remember it's the the liquid going through the hole not the gas so if that's true then a small hole would let less liquid out. ???
This is a good one for picking our brains.
Mike
No, I don't think it is liquid going through the cart hole but gas. Remember, the cart itself is only partially filled with liquid and a portion of it is space which becomes gas immediatly, so the flow from cart to valve would be gas, not liquid.
Rich
At 70 degrees F, CO2 obtains a gas pressure of 852.8 psi when confined in a vessel. If there is more CO2 in the vessel, it will be have to be in liquid form. So, the state of CO2 in a pressure vessel, such as a powerlet at room temperature, is a pressurized gas above a liquid. If the gas is released, such as through the operation of an airgun valve, some of the remaining liquid flashes to gas until the pressure is equalized for that temperature.
It's important to understand that CO2 pressure is determined by temperature, not by mechanical compression. If you were to compress gaseous CO2 by mechanical means, it would turn into liquid when the right pressure was reached. The pressure in a 12-gram powerlet remains constant until all the liquid is gone. A powerlet has the same internal pressure as a 10-oz. bulk CO2 tank when both are at the same temperature. Therefore, CO2 guns do not lose velocity as you shoot them until all the liquid is gone and they start to run out of gas.
Also, keep in mind that CO2 is a refrigerant gas. That means it cools when it expands by flashing from liquid to gas. Therefore, when you shoot a CO2 gun rapidly, the gas will cool the gun parts considerably. Because CO2 pressure is based on temperature, the pressure in a CO2 gun will drop if a series of shots are fired in rapid succession. In practical testing, I've seen velocities decrease by more than 100 fps over a long string of shots. That will affect where the pellet strikes the target unless it's very close to the shooter. So, if you want to shoot accurately with a CO2 gun, do not shoot rapid-fire. With a target pistol, I like to allow at least 15 seconds between shots so the gun's temperature can cycle back to where it was before the shot. But, if you're just plinking, you can shoot faster than that.
Carl
In the movie "Where Eagles Dare", Major Smith (Richard Burton) said, "A hole is a hole is a hole, as they say". ;)
I've noticed this seeming anomaly with some of the CO2 cartridges I've used. But, unless the seal was not entirely punctured, performance has always appeared to be the same.
JEBert's comments were on a 1377, not a 22XX gun...
I'm with the "crushed" seal or a seal that has taken a "set" and is now shaped like the co2 cap :-*
Quote from: BDS on May 23, 2013, 08:37:05 PM
JEBert's comments were on a 1377, not a 22XX gun...
I'm with the "crushed" seal or a seal that has taken a "set" and is now shaped like the co2 cap :-*
It was actually that I had the trigger over travel screw in too far where the trigger wasn't fully letting the seer move away from the hammer. The seer was dragging the on the hammer and wasn't striking as hard as it should which was making it not puncture the c02 cart all the way. I'm thinking the seer dragging like that was also the reason that it seemed my fps had dropped because I was shooting low from where I had previously sighted my scope. After I fixed the problem and went back out to shoot, I was now hitting high from re sighting the scope for the lost power from before.
By golly, wheres Ed when ya need him?
Quote from: mr007s on May 23, 2013, 10:37:06 PM
By golly, wheres Ed when ya need him?
LOL I have to stick to my guns, small hole less big hole more.
Mike
I was indeed talking about the sear drag on my hammer in a 1377 gun causing the valve not not release more than 6 pumps when I had the over-travel screw adjusted too tight. I would think that it would have the effect of not holding the valve open as long in a 22XX gun the same as it did in my 1377 in addition to not piercing as big of a hole in the cart in a 22XX gun.
Cheers,