There's been lots of discussion about the Hammer Debounce Device (HDD), what it does and mostly, does it work? Well, I too was skeptical because the first one I installed seemed to yield nothing tangible. But when I think back on it I installed it on a HPA powered gun and while it did a few things I was not really aware of till now, it mostly appeared not to work.
So after doing some more research on the various forums I decided to conduct another test and this time I would use CO2 powerlets. After all, the HDD was designed to help shot count when the gun is powered by CO2, and in particular, powerlets.
So why is a HDD necessary? Well, glad you asked that. The problem with the Crosman 22xx CO2 guns is hammer bounce (repeatedly hitting the exhaust valve, releasing small burps of CO2) and that wastes gas. So anything you can do to keep the hammer from repeatedly striking the valve will improve (lessen) the CO2 usage. Therefore, less CO2 gets wasted when the hammer isn't bouncing into the valve multiple times per trigger pull. The design of the HDD for Crosman pistols allows the hammer to fly forward without any drag, but as soon as it starts snapping backward the HDD expands against the walls of the bolt bore and brakes it. This stops the hammer from opening the valve multiple times as it bounces back and forth between the hammer spring and valve spring tension, which obviously just wastes gas.
The HDD fits over the hammer's cocking pin, with the slot/opening facing backward. The opening/slot is what makes the device expand; the hammer snapping backwards makes the pin attempt to back out of that opening/slot and makes the body expand in the bolt bore, creating friction to slow the hammer. Forward motion isn't restricted though, so your shot velocity remains unaffected. You just get way more shots per fill since it isn't re-opening the valve after the pellet's already gone.
It's also worth mentioning that the gun is a lot quieter with the HDD installed. I actually shot the string with the HDD installed first, and then took it out to shoot the "without HDD" string. The gun sounded like a cannon after I'd gotten used to the quiet volume of the gun with the HDD.
The gas release due to hammer bounce occurs so late in the firing cycle (because it takes more time to for the hammer to complete the first rebound from the spring than the pellet needs to reach the muzzle), that the pellet is already gone from the barrel. So that gas has nothing to do with its energy - except make noise. Hammer bounce actually accounts in this way for most of the muzzle blast of an otherwise efficient airgun. That's why making that spurious waste of propellant go away by adding an HDD also makes the gun quieter, much, much quieter.
The "other" way to subdue muzzle blast - fitting a LDC - just hides the problem: cuts noise while doing nothing about the underlying cause of the noise (and waste of air).
On the HDD install... When you install the HDD, be sure to lube it up with some Pellgun oil or non detergent 30 wt. motor oil. Be sure you don't try to force anything when you install it.
The critical step is mating the receiver to the tube. Be sure the alignment of the hammer/striker cocking pin is correct and slips into the hole in the HDD. You don't want to crush the hook at the rear of the HDD.
As with all testing your mileage may vary greatly from mine. But let me say I'm convinced and will be adding HDDs to my CO2 powered guns and I think you should also. Look at the data and make up your own mind. Incidentally, I didn't just run this one time but ran it about six times and the results were all quite similar.
Carl
hold on. so your getting 86 + shots from one Co2 powerlets using a HDD?
What airguns100 said.
That is quite spectacular in terms of economy, think how many shots one would get from a bulk tank with those results, a near 50 percentgain in shots per 12 gram powerlette is nothing short of amazing :-*
actually is it not more than 100% increase in shots ???
anyhoo i dont believe your results perhaps you should send me your hdd and ill test it myself :P
i have heard good and not so good things about these HDDs and if you get 1 that works along with power adjuster you can still do better yet (best used for plinking and paper punching ;) ) what caliber were you using for this test ?
The gun I used was a brand spanking new 2240 taken right out of the box, indestructible danged hard plastic package, and used for these tests. And as I mentioned I ran the test six times and what I published was the best run. Worst run as 76 shots from a single powerlet.
Carl
Philbert, ops,. you are right about that, it is 100 percent more :)
That's something that needs to be put on the top five list of up-grades, if there is such a list.
I'm surprised Crosman hasn't factory installed something like this.
Quote from: airguns100 on January 27, 2011, 09:08:04 PM
That's something that needs to be put on the top five list of up-grades, if there is such a list.
I'm surprised Crosman hasn't factory installed something like this.
that would cut into the co2 profits ;D :)
Quote from: eric on January 27, 2011, 09:12:55 PM
that would cut into the co2 profits ;D :)
True. How ever it's made out of "plastic". :P ;D
here is something from the green from a little while ago from lon and steve http://www.network54.com/Forum/275684/message/1250518993/I+don%27t+think+anybody+has+done+better+re-++2240-50+shot+count+and+consistency--- (http://www.network54.com/Forum/275684/message/1250518993/I+don%27t+think+anybody+has+done+better+re-++2240-50+shot+count+and+consistency---)
Got HDDs in both of my Crosman Co2 guns. Made a believer out of me a long time ago. They DO work.
I am wondering why the lower velocity at the beginning of the string. Any theories?
Maybe something to do with the co2 stabilising after the initial puncture/release and a temperature shift? Maybe? :-[
Amazing that a $20 piece of plastic would do that, huh? LOL :-*
I grasp the concept of how the HDD controls the repeated motion of the hammer, really I do. Thanks to the detail spooned up in the opening post by Carl. This got my mind wondering (sometimes good, others not so good.). The Disco tube and hammer were out on the workbench/kitchen table so I zeroed the calipers and took some measurements. The I.D. of a Disco tube is .748. I will carry it to work tomorrow and use some hole mics on it for checking roundness and a closer overall diameter. The Disco hammer measures .736". I'm thinking the tube is probably .75 so that leaves .014" of play for the hammer to bounce around in.
I am wondering to myself if this was closed up some with a very small amount of play if the hammer would react differently to a degree when the trigger is pulled. Would bounce be lessened any? A light coating of moly paste would aid in the forward motion. Just wondering about this and would like members thoughts in this area.I have the experience and machinery at my disposal to fab one and heat treat it but would the benefits be worth the time?
I think that with the moly and perhaps a tighter fitting hammer it would still suffer from the infamous bounce problem. Gotta remember that the HDD acts like a brake to basically stop the hammer after the initial contact with the valve and the beginning of the backward motion.
Carl
How about other pistols? we are crosman orientated but wouldn't a benj EB gain something by a HDD? are there any that fit with a EB?
If thats what results they give then got to get one,any one know a supplier in the uk?
Quote from: Oane on January 28, 2011, 06:55:27 PM
How about other pistols? we are crosman orientated but wouldn't a benj EB gain something by a HDD? are there any that fit with a EB?
i don't think there is ,only the crosman (style/s) and rjmachine breeches(closer tolerences).the eb reciever is different than the aboved mentioned.think someone tried it a few years back but looks like nothing came from it.the benjamin/sheridan rifles on the other hand, yes but they are different in design
There is one designed for the QB-78 series of rifles. I think Steven Archer commissioned Steve-of-NC to design one for them. Not sure of any others though just as Eric mentioned.
Carl
Wow, Carl--those are some spectacular results!
It's strange that I get nothing like this with my AoA HDDs in my 2300S'. Since I now have one gun with and one without, I can testify there's no difference in noise level, nor (before I went bulk) any difference in Powerlet consumption. I always got between 65 and 75 consistent shots/Powerlet--before installing the HDDs and after one broke (yep, the little hook busted off). Of course, the 2300 series have a volume reducer in the valve, but I can't see how this would reduce hammer bounce. THe absolute only time I notice any bounce is when the guns are running out of gas--they kind of "burp" and that's my warning to refill--and both guns do it the same.
I wonder if your home made HDD has closer tolerances than the ones from AoA? Or did I just get unlucky and buy a couple of lemons? Getting twice the shot count/fill and less noise would be a dream come true!
Timm.
How many shots did you get with the one I sent you before it self destructed?
Thanks,
Rich
I actually had three of the HDDs, two from AoA and the other from ArkMaker. Don't know what happened to the first one. And actually I think I decided it did NOT work and discarded it. The AoA second one yielded the best results but remember it was installed on a brand spanking new 2240 and was the only mod done to the gun. The 2300 is a different animal entirely.
Rich. I was right at 45 shots when it failed. The hammer pin just kept going right through the groove that was supposed to act like the brake.
Carl
Does anyone have a link to an old thread that showed installing one of these HDD?
Not sure who posted it before, it had pictures but I can't find it! ;)
I can't quite visualise how it fits from the description :-[
Quote from: quickster47 on January 30, 2011, 01:43:31 AM
Rich. I was right at 45 shots when it failed. The hammer pin just kept going right through the groove that was supposed to act like the brake.
Carl
Well, I'll just have to try again!! :-*
Rich
https://www.airgunsofarizona.com/ (https://www.airgunsofarizona.com/)
Look on the left for Crosman
then Custom Parts
Installation guide is a link under the pic of the HDD
Ah-HA! :D
Thanks, thats the one! :P
Who sale these????????????????????????????
Where can i get one???????????????????????
Do you someone have a photo of the internals and instalation?????????????????????????????
Quote from: redpuntohgt on January 31, 2011, 09:19:20 AM
Who sale these????????????????????????????
Where can i get one???????????????????????
Do you someone have a photo of the internals and instalation?????????????????????????????
redpuntohgtHave a look at
Arkmakers post, the one before mine.
Theres a link and instructions for the HDD.
Cheers :-*
I am blind :)
Thanks a lot friend! :-*
Quote from: redpuntohgt on February 01, 2011, 09:21:47 AM
I am blind :)
Thanks a lot friend! :-*
NP. Happens to me all the time! :-*
The Airguns of Arizona get the money but didn't send anything and nobody answer to my e-mails
do you know any other place that i can buy safely this part? (HDD)
Quote from: quickster47 on January 30, 2011, 01:43:31 AM
The AoA second one yielded the best results but remember it was installed on a brand spanking new 2240 and was the only mod done to the gun. The 2300 is a different animal entirely.
The main difference between the 2240 and 2300 series, as far as the HDD is concerned, is the steel receiver on the 2300 vs. the plastic one on the 2240. I can see how the HDD would likely have a much higher coefficient of friction against plastic, which would possibly explain the difference in results we've gotten.
redpuntohgt--try calling AoA on the phone. I've done a fair amount of business with them, and have nothing but good experiences to report. They've called me a couple of times when I've tried to order something that was out-of-stock, and every time we've resolved the problem quickly and to my satisfaction.
Timm