Swiss Arms (Sig) SG 553 SOW Commando

The rifle action is gas piston driven with the piston located above the barrel and forward of the bolt carrier. Control and return of the piston is managed by a captured recoil spring system with the recoil spring placed around the piston (This setup is derived from the Sig 551 in contrast with the AK/Galil/LM system – the 552, which has been replaced by the 553, utilised a recoil spring system similar to the AK/Galil/LM design with the recoil spring positioned rearward of the bolt carrier). The bolt carrier and the piston are linked by the removable charging lever. Disassembly of the bolt carrier and piston is achieved by detaching the removable charging lever.

A polymer overmolded charging lever is located on the right hand side of the receiver (similarly positioned to the lever on the AK/Galil/LM rifles). The bolt locks open on an empty magazine (contrary to the AK/Galil/LM mode of operation).  Bolt release is managed by utilising the bolt release button located on the left hand side of the receiver which works great for speedy and easy charging of the rifle after a loaded magazine has been seated in the lower receiver

Specs

Barrel length excluding flash hider = 230mm
6 Groove barrel with a 1:7 twist rate.
Weight empty 3.2kg/7lb
The rifle has a max length of 730mm and a stock folded length of 501mm.