Alexander Arms AR-15 Upper Receiver Build Kit - 50 Beowulf, 16.5" Barrel, 49/64"-20 Thread, Black Finish

The Alexander Arms AR-15 Upper Receiver Build Kit in 50 Beowulf gives you everything you need to assemble a complete upper receiver for a cartridge that hits different on the range and in the field. This 16.5" barreled kit is purpose-built around the 50 Beowulf round—a hard-hitting intermediate cartridge that brings serious punch in a modern sporting rifle platform. Whether you're a builder who likes hands-on control over your rifle's assembly, or you're exploring what the 50 Beowulf round can do, this kit eliminates the guesswork of sourcing individual components and gets you to the range faster.

The kit ships with a complete upper receiver, a matched bolt carrier group (BCG), gas block, gas tube, and dowel pins—all the critical parts needed to turn a lower receiver into a functioning rifle. The 16.5" barrel features a 49/64"-20 thread pattern and ships with a thread protector, so you can mount a suppressor, muzzle device, or other accessory down the road if needed. Black finish across all components keeps it clean and versatile.

50 Beowulf upper builds appeal to hunters, recoil-sensitive shooters, and anyone curious about alternative calibers that deliver stopping power without the blast and recoil of larger magnum rounds. Assembly requires basic AR gunsmithing knowledge and the right tools—this is a DIY kit, not a plug-and-play solution. If you're new to builds, pair it with a reliable lower receiver and consider a reference guide or video before you start.