Models 5.56 semiautomatic rifle. WIP 40 236 0 Mosin Nagant bolt head for 12mm/.473" cartridges 29 193 1 AR-15 sheet metal and tube steel upper receiver 26 206 1 trunnion for a "tubeless" direct impringed rifle 13 91 0 delayed blowback carrier for HK bolt 41 290 9 G3 HK91 Stripped Bolt 43 439 4