AR-15 in 9x25 Dillon. Can it be done?

[Demitrios]

The thread says it all. I know Olympic Arms makes an AR-15 upper for the 10mm so I started wondering if it were at all possible (I'm not asking if it's practical, I already know the answer to that one) to actually make this happen. I would imagine you'd need a 10mm upper, 10mm mags and a 9mm barrel reamed out to accept the Dillon.

Oh and to all of you who covet this rifle/round please no comments on how dumb or pointless an idea this is. I simply have a question that needs an answer.

 

[DWFan]

I'm not that familiar with these rifles, but I don't see why it couldn't be done. I've wondered why a .357 SIG version wasn't done long ago if for no other reason than to increase the popularity of the cartridge.

(Edit) I found these guys...http://bazookabrothers.com/products2.htm

 

[MachIVshooter]

I'm sure it could be done in pretty much the way you describe.

Personally, I would only have it in an SBR configuration; the round would gain very little in more than 10" of barrel.

I do want a 10mm AR SBR, but Oly's only come with ONE 19-round mag. Kinda stupid, since I can slap a 21 rounder in my Witness Limited and have a much more compact package.

 

[Zane]

I'm sure it can be done. I've even thought about it myself.

I am not a gunsmith by any stretch, so what I'm saying should be taken as uninformed musings. My issue is that it would be blowback. While that is fine for 9mm and .45, 9x25 Dillon is a high kinetic energy, high impulse cartridge. I shot some of my 9x25s from a Glock 20 with a standard recoil spring and it was clearly unlocking before the pressures were down to safe. If you are playing speed demon with 95 gr bullets, I'm not sure I'd want to risk straight blowback. I know the BCG is higher mass than my slide and you can beef up the buffer and recoil spring, to delay unlocking, however that seems to defeat the purpose of using an AR15 pattern.

An AR15 is a gas operated rifle and the 9x25 Dillon is a high gas cartridge, that in some loadings has similarities to lower pressure rifle cartridges. Ideally, you'd use the gas to delay unlocking, fixing the potential blowback problem. In that case, you could likely lighten the BCG, buffer and the rifle.

Some people have managed to make gas operated 7.62x25mm AK47s. I have to think one could be adapted to 9x25 Dillon.