Models 5.56 semiautomatic rifle. WIP 41 243 0 Mosin Nagant bolt head for 12mm/.473" cartridges 29 198 1 AR-15 sheet metal and tube steel upper receiver 26 210 1 trunnion for a "tubeless" direct impringed rifle 13 92 0 delayed blowback carrier for HK bolt 42 300 9 G3 HK91 Stripped Bolt 43 451 4