[donmeaker]

An adjustable gas system means there is a design problem. Why have a gas system that needs to be adjusted. Better to make it strong enough to work, and buffer it as needed when all the power is not necessary.

[RoosterRedux]

The Sig piston system is also adjustable and I don’t think there is a problem. My Ruger SR 556 adjustable piston helps me shoot a wider range of power re: ammo and still achieve optimum bolt carrier group operation.

[MasterGunner01]

An adjustable gas system does not necessarily mean a design problem. There are times when it is useful — operating with different weight bullets than the usual 147-150 grain or under severe environmental conditions. My concerns are felt recoil and muzzle blast from the carbine barrel.

I had an AR-10 rifle that was built from Portuguese parts on a U.S. semi-auto receiver. For some reason I still do not know, that rifle really beat up the shooter when fired. I eventually sold it to an ANG officer who wanted an AR-10 for his collection.