Description

AR57 ULT Upper Receiver 5.7x28MM.  This upper receiver is chambered in 5.7x28mm and features a steel 16″ barrel with 1:8.5″ twist and a 1/2×28 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. The 3 slot MLOK rails will allow you to add your favorite light or optic making this one tough tactical upper. he receiver and rail block measures just over 17 inches overall length; from the receiver back to the muzzle end, the total length is 24 9/16 inches. In contrast to many other receivers, there is no gas system to become clogged with carbon or fouling; the chamber stays clean well beyond extended shooting. Convert your AR-15 Rifle to shoot the same 5.7×28 ammo as the legendary FN P-90 PDW!