Angstadt Arms AR-15 .40 Smith & Wesson Complete Bolt Carrier Group QPQ Features: When the time comes to design and build a .40 Smith & Wesson AR-15 upper you don t want to run into issues fitting parts from a countless number of manufacturers. Often times these Franken firearms leave you struggling to find the correct combination of parts in order to even get the gun to run right. Well those days are over thanks to Angstadt Arms. The Angstadt Arms AR-15 complete colt carrier group is compatible with GLOCK pattern magazines. Additionally this carrier is compatible with a standard AR-15 hammer no need to try and search for a specific hammer. The unit is machined from 8620 alloy steel and features a QPQ Quench Polish Quench Nitride Black finish. Moreover if you intend on using this unit with the Law Tactical folding stock adapter it has a removable weight in order to support the Law adapter. Angstadt Arms AR-15 .40 Smith & Wesson Complete Bolt Carrier Group QPQ Specifications: Angstadt Arms AA40BCGNIT AR-15 Complete Bolt Carrier .40 Smith & Wesson Compatible with Both GLOCK Magazines For Use with Standard AR-15 Hammer Features removable weight for use with Law Tactical folding stock adapter Machined from 8620 Alloy Steel QPQ Black Nitride Finish Mil-Spec AR-15 Upper Receivers