Panzer Arms AR57 Ultra Light Tactical 5.7x28mm Upper is a complete upper receiver that converts any mil-spec AR-15 lower to shoot 5.7x28mm ammunition. This alloy monobloc receiver is built with a 16-inch steel barrel, perforated muzzle brake, bolt carrier group, buffer, and screws.

This AR57 Upper Receiver Assembly converts any AR-15 lower to a rifle capable of shooting 5.7×28 ammunition. The unique upper design loads from the top and ejects downward through the AR-15 mag well.

This upper receiver is chambered in 5.7x28mm and features a steel 16" barrel with 1:8.5" twist and a 1/2x28 thread pattern. This AR57 Upper is constructed with a steel barrel, muzzle brake, bolt carrier group, buffer, and screws, all built into an alloy monobloc receiver.

Convert your AR-15 type rifle to shoot the same 5.7x28 ammo as the legendary FN P-90 PDW! This AR57 Upper is constructed with a steel barrel, muzzle brake, bolt carrier group, buffer, and screws, all built into an alloy monobloc receiver. In other words, it is ready to drop in and push pin. It is also built as solid as a tank.

The AR57 ULT Complete Upper Assembly, chambered in 5.7x28mm with a 12" lightweight barrel and M-LOK rails transforms any AR-15 lower into a 5.7x28 firearm. Featuring a unique top-loading design that ejects downward through the AR-15 mag well, this lightweight upper features a stronger, lighter rail with a melonite black coating.

Factory New - comes with a 16" lightweight barrel with M-LOK rails. This AR57 AR57 Upper Receiver Assembly converts any AR-15 lower to a rifle capable of shooting 5.7x28 ammunition. The unique upper design of these AR15 Upper Receivers loads from the top and ejects downward through the AR-15 mag well.

This AR57 Upper Receiver Assembly converts any AR-15 lower to a rifle capable of shooting 5.7x28 ammunition. The unique upper design loads from the top and ejects downward through the AR-15 mag well. The new generation upper has a stronger, lighter, and more streamlined rail; finished with a beautiful ultra-smooth melonite black coating.

The AR57 Upper Receiver Assembly converts an AR-15 to shoot 5.7x28 FN ammunition. The unique upper design loads on top and accepts FN PS90 magazine (not included) and ejects downward through the AR-15 magwell. This upper is precision machined from a one piece aluminum forging.