I haven’t heard as much about the gas pistons lately. Fad? Or slow to catch on? I know those Korean Daewoos have them and they work good with a gas piston system.
There are more and more gas piston models going on sale.
The AR is the only major direct impingement rifle on the world market, most everyone else except the Germans uses piston drive.
The Marines also seem pretty happy with their new M27 H&K gas-piston equipped SAWs. The introduction of a reliable 225-round magazine hasn't hurt that little innovation a bit, and the $23.6 million worth buy now gives the Marine fire teams so equipped a weapon light enough that the team's SAW gunner can keep up with his three buddies as they go about their business.