F-1 Firearms BDR-15-3G Receiver Set is a modern take on the MIL-SPEC M16 of yester-year. This set was meticulously engineered to be as lightweight as possible, while remaining rigid and cosmetically pleasing. All areas not inherent to functionality have been stripped away, leaving a beautiful base for any build. Each set is hand finished and matched in-house, for the utmost in operational and cosmetic perfection that our customers have come to expect from us here at F-1. BDR-15-3G sets accept all MIL-SPEC patterned parts as well as Magpul mags.