Models 5.56 semiautomatic rifle. WIP 43 259 0 Mosin Nagant bolt head for 12mm/.473" cartridges 30 216 1 AR-15 sheet metal and tube steel upper receiver 29 218 1 trunnion for a "tubeless" direct impringed rifle 14 99 0 delayed blowback carrier for HK bolt 43 317 9 G3 HK91 Stripped Bolt 46 499 4