MMC AR-15 Upper Complete

These are really nice, Function Tested, and ready to drop in to any lower and start firing... Upper is machined from 7075-T6 forgings that are hard coat anodized for wear and scratch resistance meeting MIL SPEC Barrels drilled, reamed and buttoned from 4140, 4150 Chrome Moly, Chrome Moly Vanadium per MIL –B-11595E or 416 stainless gun quality steel then stress relieved prior to contouring and chambering. Twist rate is 1 in 9. The barrels are marked 5.56 Nato and therefore chambered for and suitable for firing either the Nato 5.56 designation or the .223 Remington commercial round. The head space is set and the barrel is tested for straightness using a 6” drop pin gage. The steel barrel assemblies are Parkerized to eliminate rusting. Bolts machined from tool steel, hardened and tempered to provide maximum wear characteristics then Parkerized to eliminate rusting. Bolt carriers machined from 8620 gun quality steel, heat treated and tempered to maximize strength and wear characteristics then Parkerized to eliminate rusting. These work great with our complete lowers...