Sig Sauer SIG516 G3 11.5" Pistol

The SIG516 G3 11.5-inch pistol is the short piston AR in SIG's third-generation 516 family. A short-stroke pushrod drives the bolt carrier, so combustion gas and heat stay forward of the receiver instead of blowing back through a gas tube. The gas valve has three positions, which is the setting that matters on a suppressed 11.5: you can open it for a dirty gun or weak ammo, and you can step it down when a can raises back pressure.

Controls are ambidextrous, and a steel non-reciprocating side charging handle sits beside the standard rear handle. That lets you press-check or clear a stoppage without breaking a firing grip. The 11.5-inch cold-hammer-forged barrel is 1:7 twist with a SIG flash hider-compensator on 1/2x28. The free-float M-LOK handguard and Matchlite Duo curved trigger match the 16-inch G3 rifle. Overall length is 28.3 inches collapsed and 30.3 inches extended. Weight is 7 pounds with a magazine.

Seven pounds is heavy for an 11.5-inch 5.56 pistol, and that is the piston trade: cleaner suppressed running and a tunable gas valve, with extra mass and a more involved parts count. The factory pistol configuration avoids an SBR stamp. Unsuppressed blast from 11.5 inches of 5.56 is still sharp, so a can is the usual next part.