[Spktyr]

Notice the gas piston system the US Government bureaucrats won't adopt (except the Marines did an end run around them with the M27 IAR) that eliminates the problem completely.

[MaxMax]

I might rather have the Gas with the Bolt above since the Relia-bolt will blow
out the carbon buildup at the barrel because of the tapering. Piston will
buildup carbon also at the rod under the hand guard and adds extra heat up there.

Personally I would rather deal with the Carbon at the barrel where it can be blown out
by just discharging the wep. Cleaning up front would just add more of a pain in the
process of cleaning and recovery. The Bolt carrier together eliminates the problem
of keeping the carrier wet to an extent. They say it doesn't require oil because
of the coating. Still not sure about that one though and I've since began using Cerflon
on all moving parts.

Then the extra movement up front might get interesting.

Just cannot win with that carbon! lol..

Just my thoughts on it.

[MHGinTN]

A few years ago I installed and tested the Osprey Defense piston kit on a carbine AR15, the Adams Arms on the same length system, and the CMMG system. After a thousand rounds through each I found the OSprey to be far superior to the other two, and the Adams Arms to be better than the CMMG. The Osprey system has the fewest parts to deal with and darn near cleans itself with the piston cup being kidney shaped. It does build up heat fast out front, but the reliability is amazing. The Adams Arms unit had the ability to dial gas charging, so when shooting at distance the gas could be turned down or off and single the cycle. of the three, the Adams Arms with adjusted gas output functioned best in full auto. The barrel was H barrel not a pencil type.