GC_UPC Geissele Super Duty MOD1 5.56 NATO 10.3" 1:7" CHF Chrome Lined Bbl DDC Complete Upper Receiver Group 08-543S MAP 08-543S show more like this Free Shipping over $250 Eurooptic GC_UPC Geissele AR-15 Super Duty MOD1 Upper Receiver Assembly 5.56x45mm 10.3 Cold Hammer Forged Barrel M-LOK - 796015" $1,410.00 08-543S show more like this 13.50 MidwayUSA