What are my options for a silenced 7.5" Piston driven AR pistol?

[BearClaw Bigsby]

I hope this is in the right forum.

I am looking for a piston driven 7.5" AR upper to be used with a silencer. I have really only seen two 7.5" uppers. The Noveske is a little out of my price range and gas driven, and the RRA, although piston driven, says it is not compatible with suppressors.

Is there anything else out there? Would it be hard/easy/practical to convert the noveske to piston and would it be able to accept a suppressor?

[sandsunsurf]

You're sure to get plenty of conflicting answers on this one... Here's some info to start you on your way.

PWS makes a 7" upper called the Diablo, which is a piston design. I'm not sure of reliability if you remove their Diablo comp, but I'm sure it could be done. It's a good upper, that works well for a lot of people.

Adams Arms makes a 7 or 8" upper, which should run relatively reliably, using the AA piston system. I've shot maybe 1000 rounds through one, mostly full auto, and I didn't have any problems, but there are plenty of people that will report otherwise. Mine was a test upper, and had been well broken in before I ran it.

As for a suppressor, the only can that I know of that is warrantied for use on a 7.5" barrel is the AAC 7.62-SDN-6. The others will not be warrantied unless they're on a 10" or longer barrel. The good thing is that the SDN-6 can be used on a lot of different guns. It will probably be my next suppressor purchase.

You are probably going to get lots of "don't do it" responses. You're the only one that can decide what you want to do, but you're likely designing a gun that is a "range toy" with questionable long term reliability.

[shadow65]

CMMG has a 7.5" piston upper I tested. Ran fine.
I used a 7.62 suppressor on it.
At about 400 rounds a copper ring broke loose which caused the carbine to short cycle when the can was taken off.
CMMG has since changed the design with a one piece plug and a stronger piston block without the copper seal.
I have an 11.5" CMMG piston upper that runs like a champ.
Dave N