553-28 553 Firing Pin
553-29 553 Hammer Fixed Set
553-32 553 Fire Control Pins
553-34 553 Automatic Firing Pawl
553-M-01 553 Magazine Spring & Follower
553-M-03 553 Magazine Feedlips & Gas Router
553-M-05 553 Magazine Lever Set
553-M-07 553 Magazine Inlet Valve
553-M-08 553 Magazine Gas Tube Cap
553-M-09 553 Magazine Base Plate
553-33 553 Safty Spring
553-15-3 553 Nozzle Buffer O-Ring
