The SU-16 has a conventional long-stroke gas-piston operation and utilizes the proven Johnson/Stoner breech locking system. It is compatible with standard AR-15/M-16 magazines. The reciprocating bolt handle and magazine catch are on the right side while the push bolt safety can be changed to work from either side. Except for barrel and operating components the SU-16 is made entirely of high impact reinforced polymer.