SpudFiles

Hey guys, I'm making a high pressure copper coax that will shoot .22 pellets. For a barrel, I am planning on 1/4" OD K&S brass tubing with a .014" wall, which makes the ID .222". This would of course be a smoothbore, and I have read that diablo shaped pellets perform well without rifling. Legit diablo pellets are a bit more expensive though, so I was wondering if a pellet like the following is basically the same as a diablo:

http://www.amazon.com/Crosman-Domed-Pre ... ellets+.22

These crosman pellets appear to have a similar shape but I'm not entirely sure. I want this gun to be as accurate as possible! Thanks guys

The skirt is too shallow, they will tumble. Modern airgun pellet designs assume rifled barrels.

Why don't you just buy a spare Crosman barrel?

http://www.dlairgun.com/Accessories/Cro ... arrel.html

Seriously just $25. You're an American f'r chrissakes!

jackssmirkingrevenge wrote:Why don't you just buy a spare Crosman barrel?

http://www.dlairgun.com/Accessories/Cro ... arrel.html

Seriously just $25. You're an American f'r chrissakes!

X2....Jack, you did know that D&L is Canadian??

Being an 'merican, gunfreak can order direct from Crosman...for even less.

http://www.crosman.com/cs/contact

I don't think the breech on a crossman barrel would allow for use in a coaxial... I could be wrong though. I have already made my barrel assembly and the epoxy is curing. So basically any pellet that isn't "diablo" will tumble?

No hard and fast "rule" that says you cannot add the barrel after the valve...treat the co-ax itself as a sort of toolies valve with extra dead space behind projectile. Wouldn't be the first time that such a compromise was made to achieve a desired configuration.

Sort of a moot point if the epoxy is already curing though.

Pretty much most airgun pellets are "diabolo" in shape....the heavier ones tend to be less biased with respect to mass forward...would stick to the "standard" weight types (7.9gr in .177 and 14.3gr in .22), which coincidentally...are the most commonly stocked ones.

http://www.pyramydair.com/blog/2005/12/ ... sizes.html

Gippeto wrote:Jack, you did know that D&L is Canadian??

Very much

I don't think the breech on a crossman barrel would allow for use in a coaxial...

You have a hacksaw and a sort-of lathe to smooth it off, what's the problem

You're looking for medium weight pellets as Gippeto said, with a deep hollow in the skirt.

JSB exacts have this sort of shape:

Thanks for the pointers. I found some .22 round lead balls online and went ahead and ordered them. They should give me decent accuracy, but I'm still curious about pellets. I think I'll just try the crosman dome heads. If they aren't very accurat it's not a huge loss because they can always be used for shorter range shots. I found some heavy diabolos that might work well too... There is this sampler tin with different pellet shapes that would help me determine the best pellet shape. Might get that eventually. One more day to initial testing! Gotta wait a few more days for my bbs to arrive though.

I still think you should go for a rifled barrel, they are cheap and available!

If this setup doesn't work well, I will definitely consider using a proper barrel. I didn't think to use a rifled barrel for this project until you guys suggested it, and they really are pretty cheap. Definitely an option if I can't get this gun to shoot accurately.

Initial testing was a disaster. The epoxy that sealed the barrel and chamber dripped down the inside of the chamber because I didn't seal it well enough, so about 3mm of epoxy accumulated on the face of the piston. Just a disaster. I didn't even mix it right so it didn't cure hard. I ripped it all apart, salvaging everything, miraculously. Cleaned it all up and re-epoxy'd it all up. Did it right this time, so tomorrow morning I find out if this thing will even shoot. My bbs will arrive in a few days so we can see how accurate it is.

Gun Freak wrote:The epoxy that sealed the barrel and chamber dripped down the inside of the chamber because I didn't seal it well enough, so about 3mm of epoxy accumulated on the face of the piston. Just a disaster. I didn't even mix it right so it didn't cure hard.

You mean to tell me that you, the master of epoxy, have made a mixing mistake?? I'm in shock!!

I had my early days too, I also remember coming back from school excited to try out a new project only to find it had been fused solid by an unexpected leak. We're talking 15 years ago, but you don't forget these things man...

You learn from your mistakes I guess haha. I will never cast epoxy without sealing the mould ever again

Gun Freak wrote:I will never cast epoxy without sealing the mould ever again

Words are just that my friend