22xx tube bleed hole and Disco valve

[Poor-man Plinker]

Thanks Sean,

I will be laughing all the way to the audiologist's office. Or, maybe on my way to the drill press... Wait a minute, I don't have a drill press so I might as well go to the audiologist. he he he

This is another one for the "When I grow up, I will figure it out" catagory.

[sholo]

Not being funny- but I'm not so sure 10fps on a 600fps+ gun is indicating there was any gain specific to the hole- maybe you cleaned some crap off the hammer, or re-positioned the hammer spring or ...

Not saying this isn't valid- but on gains below 2% it strikes me that just about anything could do this, perhaps something completely unintentional. Now if you could do 10 simple things that add 10fps each...

You (and Bob) may very well be right, and it's just my inexperience getting the better of me (again)...

Well....this is bugging me now! I'm going to fill bottle, take 10 or so shots the way it is configured now, then take stock off, put some duct tape over the new bleed hole only, and take 10 more shots to see if there is any difference in fps. That way I'll know for sure if it (new hole) has any impact on velocity at all.

And, just to clear - I am NOT doing this to prove anyone right, wrong or otherwise, but more to satisfy my own curiousity. It's all just part of my learning curve! If in fact there is no difference, then this thread should be deleted as all I've done is waist forum space with false information...

@ Sean: I guess I have to eat some crow on your "bullsh!t" call, now don't I?.... Lasted all of what....3 days???

Todd

[sholo]

Well , I finally tested my bleed hole theory, and the results were less than stellar. Put some duct tape over the hole, grabbed some H&N FTT (14.66 gr), fired off 10 shots and averaged 978 fps. Took tape off, fired 10 more shots and averaged 986 fps. A whopping 8 fps difference!... Even at that, I'm not so sure the bleed hole had much (if anything) to do with it, but more to do with reg pressure fluctuation between shots...

Oh, well, I don't consider it a failure, I just succeeded in finding out it makes no difference!

But the gun is sooo much "lighter" now with that excess material removed...

Todd

[SeanMP]

I still think it's a good theory.

If the tolerance on the hammer fit inside the tube was a little tighter you could easily be fighting an air cushion

[Poor-man Plinker]

Well , I finally tested my bleed hole theory, and the results were less than stellar. Put some duct tape over the hole, grabbed some H&N FTT (14.66 gr), fired off 10 shots and averaged 978 fps. Took tape off, fired 10 more shots and averaged 986 fps. A whopping 8 fps difference!

Todd

"Just ran some shots over the chrony (with the new bleed hole), compared the numbers to what I was getting before, and lo and behold - gained an average of 10 fps no matter what PA setting or pellet I tried"

Personally, I would not be so quick to dismiss an 8 to 10 percent increase in velocity. Until you shoot a couple hundred rounds with the hole open and a couple hundred with the hole closed it might not be considered statistically significant... I am not so sure the duct tape is adequately "sealing" the whole.. But, I actually find your results promising. I mean, tell me what other minor improvement can a person make that shows any improvement in accuracy or velocity?????

I read a lot of talk on-line about this or that "improving" performance in some vague or immeasurable way You actually have some hard numbers and I hope you will continue to explore the benefits of your discovery and examine the air cushion phenomona further. Like Eric suggested: 10% here and 10% there and they all add up.

[rsterne]

YUP!... if the 8 fps is repeatable and measurable, then you can assume you had an air cushion slowing the hammer.... I notch the back of my Disco valve to uncover the vent hole just for that reason.... I reckon it can't hurt....

Bob

[AirGunEric]

"gained an average of 10 fps ..."

Personally, I would not be so quick to dismiss an 8 to 10 percent increase in velocity...

You did not see an "8 to 10 per cent" increase in velocity unless your gun only shot 100fps to start with.

I still think that until someone actually proves the argument on their specific gun by disassembling, lubing, re-assembling, testing, then making the expanded hole change and re-testing with the exact same state of parts and lube in place, the 8-10fps increase in velocity is essentially meaningless- nothing has been "proven" other than manhandling the gun may have gained 8-10fps- which could have occurred by someone's hot little hands holding the Co2 tube or putting the Co2 caplets in their pocket while doing the work (on a Co2 gun at least).

This is the type of situation where using the same style of testing format we see from Bob is required- anything less is merely speculation/anecdotes.

[Poor-man Plinker]

OK Todd,
Ya gotta learn me something here... I'z still messin wit factory pistols and you have a 2260? with a Dicso valve? and a Mrod trigger? So does that mean you are still using CO2 caplets....????? If so I take every thing I said back because CO2 is totally unrepeatable,!!! In my experience with my factory guns, the numbers are all over the place and you might as well not waste yer time trying to find 8 to 10 fpe (not percent, thanks) repeatedly by shooting hundreds and hundreds of rounds.

If you are shooting PCP I thought it was fairly repeatable (the reason I was thinking of a hipac in the first place) If is is no better than CO2 we should both just save our money to buy more caplets ha ha ha...

Perhaps you are just a wrench junkie he he he. In which case, keep throwing money at the beast

[sholo]

the 8-10fps increase in velocity is essentially meaningless- nothing has been "proven" other than manhandling the gun may have gained 8-10fps- which could have occurred by someone's hot little hands holding the Co2 tube or putting the Co2 caplets in their pocket while doing the work (on a Co2 gun at least).

Ummm...I'm running HPA, not Co2, so I'm not sure where that came from?

This is the type of situation where using the same style of testing format we see from Bob is required- anything less is merely speculation/anecdotes.

I thought that was what I (somewhat) did. I blocked off the hole, took 10 shots (recording velocities), then re-opened the hole, took 10 more shots, and recorded those velocities. No other changes other than the hole "being there" vs not being there, and there happened to be a difference in velocity, so I posted my findings. Nothing more, nothing less. Take it for what it is...I certainly didn't intend to (or think it would) p!ss anyone off by it, or I never would have posted. But, I do hear you and totally understand - I'll leave the testing to the "experts" from now on (and no, I'm not being a smarta$$).

My sincere apologies for waisting everybody's time. I GUARANTEE you, it won't happen again...

Todd

[Poor-man Plinker]

So, serious Todd,
Do you find the HPA more consistent than the CO2 was? If you stop writing who willl I have to compare notes with?????? I cannnot keep up with Bob and Sean either, but, we both got invited to be here so let it ride dude!!!! Help me out by continuing your style of research. It is a good start in the right direction.

Do you like the HPA... Get better numbers.... better grouping????