Need advice on 22xx build

[prodigalSON]

I have been wanting to build a pcp 22xx in 9mm for some time now. Even though I have never built a gun before I have I understand the basics of airgun tuning and believe the 2240 would be a good gun to learn on. My main question is I  don't want to use a hipac so what would be the best source for a pcp tube? This will be my first build so any advice on the process will be greatly appreciated.

[avator]

This thread may interest you.
http://www.gatewaytoairguns.org/GTA/index.php?topic=93564.msg876136#msg876136

[Gertrude]

This thread may interest you.
http://www.gatewaytoairguns.org/GTA/index.php?topic=93564.msg876136#msg876136

JMO, but a 9mm/.357 build on a 22XX platform will not work very well.

  I just built a .25 cal 22XX, and I think thats about as much lead as that valve (even as highly modified as mine is),...is going to push with any useful purpose.

 For a 9mm/.357 to fly straight and remotely consistant, you would need more pressure, and more volume of air than the 22XX can safely be modified to use.

[rsterne]

I agree, unless you are really keen and willing to do a LOT of mods, building a 9mm on a 22XX platform will likely disappoint.... I built a Disco Double, modified to be safe with a 3000 psi fill, and I was able to get 9 shots at 130 FPE with 78 gr. JSB pellets (850-880 fps) and 3 shots at 170 FPE with 127 gr. bullets (770-790 fps) but you must realize that is with 250 cc of 3000 psi air onboard.... A 2260 only holds 65 cc of air (1/4 as much), and to use more than ~1800 psi safely requires significant changes.... In addition, although you can modify a Disco valve to flow enough air to get the performance above, you will need to modify the hammer and spring to be able to open it at 3000 psi.... I addition, you will not be able to safely fit a 9mm barrel into a 22XX steel breech, there isn't enough material to allow it.... A .25 cal is a relative simple conversion, however....

Bob

[prodigalSON]

I already have enough 25 cal guns. I was thinking the 9mm because I don't have one. What about a 30 cal, would that be possible? 

[rsterne]

It depends on the size tube you are thinking, that will relate to shot count.... My Disco Double, with 250 cc reservoir, gets 13 shots at 98 FPE (50 gr. pellets @ 930-955 fps) or 9 shots at 112 FPE with 70 gr. bullets (830-860 fps).... Again, those are with lots of mods and running 3000 psi.... If you use a Disco tube, figure half that many shots, for a 2260 tube only 1/4 that many at that power level.... If you drop down to 2000 psi, you may get the same shots as at 3000, but at 2/3rd the power.... Only you can decide what you will be happy with.... For a given pressure, less power will give you more shots, of course....

There is enough meat in a .300 cal barrel turned down to 7/16" to fit into a 22XX steel breech, that leaves you with about a 1/16" barrel wall, which is strong enough if you don't fall on it.... I would suggest a barrel band for extra support.... You will be faced with some challenges in machining out the breech to accept a .30 cal bolt an pellet, doable but not easy.... If you run 3000 psi, you will again be faced with fitting a heavier hammer with longer stroke and a beefy spring....

Bob

[prodigalSON]

Thank ya Bob. That was the kinda stuff I was looking for.

[Gertrude]

if it helps any,
I'm seriously considering getting a 18" barrel .22 cal from Crosman, and taking the .25 cal off.
it's OK at best the way it is with the .25 barrel, and I'd call it a 20-25 yard gun at BEST.

Sure, it would make for a GREAT "Barn Rat Gun" with some VERY fun punching power behind it,... but anything beyond that would certainly be disappointing.

Now if I only had a Barn with a rat problem..... 

[Sfttailrdr46]

   Help me out here I am a little confused where some of the modifications go. Why take a rifle that is designed to be a .177 or .22 rifle and functions perfectly within that format and try to make it something it was not intended to be ie a .25 or .30 cal rifle that will either end up under powered or possibly dangerous . The outer thing is if you use after market parts end up spending as much or more than would have been spent purchasing a rifle that was designed from the outset to be a 40 + FPE rifle of larger caliber. This is not intended as a criticism but rather me trying to understand the cost vs benefit side of it all . Thanks in advance for any positive answers to this question and if it needs to become its own thread I will move it

[rsterne]

It is a bit of a side-step on the theme of the thread, but you are 100% correct, the cost/benefit equation is way out of balance.... However, the personal pride/accomplishment equation can offset that, if that is your mind set.... It's all up to the individual.... I have never purchased an airgun that cost more than $400 (except my DAQ which I sold), but I have several that I spent much more than the price of the gun modding it.... That process has provided thousands of dollars worth of pleasure and learning to me....

Airgun - $300.... Mods - $1000+.... Knowledge gained - priceless....

Bob

[Sfttailrdr46]

It is a bit of a side-step on the theme of the thread, but you are 100% correct, the cost/benefit equation is way out of balance.... However, the personal pride/accomplishment equation can offset that, if that is your mind set.... It's all up to the individual.... I have never purchased an airgun that cost more than $400 (except my DAQ which I sold), but I have several that I spent much more than the price of the gun modding it.... That process has provided thousands of dollars worth of pleasure and learning to me....

Airgun - $300.... Mods - $1000+.... Knowledge gained - priceless....

Bob

Bob that is the answer I expected from someone with your level of expertise and I am of the same mind set but just don't have the access to a quality machine shop or the expertise to do my own fabrication of parts . Thanks for the quick response

[UCChris]

If I wanted to do a 9mm conversion I'd start with a QB78 Deluxe and HPA it to start off.

[sixshootertexan]

I agree that unless you have a way to machine your own parts it's just not worth the cost. First thing is to get an air tube big enough to supply enough air for a caliber of that size. It would have to be custom made to get it safe for 3000psi. Sometimes the cost is just to much even for the learning experience.

[rsterne]

I agree, a 9mm running on 1500 psi, to work in a QB78 tube, is going to be pretty anemic, both for power and shot count....

Bob

[UCChris]

I agree, a 9mm running on 1500 psi, to work in a QB78 tube, is going to be pretty anemic, both for power and shot count....

Bob

You know much more than I, however...

Jason built my HPA QB79 to do 30 fpe for almost 80 shots. Jason said he could most likely hit almost 50 fpe with a 78 tube. So is it crazy to think that the gun could push an 80 grain JSB at 520 fps for a 49 fpe shot? I bet he could get at least 20 shots out of it.

But again, you know more than I do about the subject. 

[rsterne]

I would define 50 FPE in 9m as pretty anemic, but whatever floats your boat.... The big pellets would pretty much bounce off the hide of a Groundhog at that velocity....

Bob

[UCChris]

Ok, point taken. I understand 9mm is thought of as a 100-150 fpe caliber.

My apologies.