Blackheart International's BHI-15 MIL-SPEC Complete Upper Receivers follow the profile of standard AR-15 mid-length systems, the BHI-15 MIL-SPEC assembly starts with an A3 flat ...

Like the early prototype ARs, the BRN-PROTO uses a flat-sided lower and a trigger-style charging handle that rides inside the carry handle upper receiver.

Over the past six months I’ve been shooting the new Bravo Company Mfg (BCM) Mk 2 Upper Receiver and rather quickly realized that the basic AR platform still had space for improvement.