Quote Originally Posted by JustMatt View Post
I chose a piston gun for the added benefits of less heat and dirt/debry/gas in the bolt area. Besides, a million AK's and FAL's can't be wrong? Can they...
Perhaps not, and while I'm not second-guessing your selection, it is probably worth noting that the AR is neither an AK nor a FAL. Here's what John Noveske had to say about the matter, once upon a time ...

Also, we should mention the poor choice of platform for the piston conversion on a round receiver bore as found on the M16/M4 system. All other piston type systems out there utilize a railed receiver design, like the M14, AK-47, M249, FAL and so on. The round receiver bore design used on the M4 is only acceptable for the standard op system. The carrier and bolt expand on axis with the bore under the normal gas impingement cycle, but on a piston gun, you run into off center impulse issues with carrier tilt and incorrectly designed carrier contact points. Some designs attempt to address the carrier tilt problem with over sized carrier tails and rollers. I do not believe the receiver extension should be used in this manner. I know many people are very happy with their piston weapons. This is not meant as a knock on the piston conversion systems out there, but as a philosophical dialogue focused the new physiological relationships applied to the M16/M4 platform through the introduction of an operating system which has traditionally been applied to receivers with rails for the bolt and/or carrier. I would rather see an entirely new weapon system designed for the piston from the ground up.
My point? Pistons are certainly worthy of consideration, but I always pause a bit when they are represented as the ultimate solution to the ARs woes, because the basic geometry of the weapon just doesn't really seem to support that assertion. Not that you ever made such a claim, of course, but I think that we're all served by a better understanding of this issue, regardless of what we happen to favor.

AC