The Rock River Arms 9 mm AR upper is available in A2 (carry handle and 800 meter backsight) and A4 (flat top) versions. Using 9mm ammunition in this AR upper will keep you shooting through the winter on indoor pistol ranges. The 9 mm upper gives you realistic recoil that you don’t get with a .22LR upper. It is ideal for law enforcement training during the long, cold winter months. The RRA AR 9mm upper is blowback operated. There is no gas system to keep clean. Both versions come with 16″ 1:10 twist A1 profile barrels made of 4140 steel. This is a small pin (0.25″) upper – please check your lower’s takedown pin diameter before ordering. On the A2 version the backsight is regulated for 9X19 mm ammunition. To use this upper on an AR lower you need a 9mm magazine, magazine adapter, action spring, and recoil buffer, sold separately.
Check the price of the RRA 9mm upper at Brownells, a name you can trust.
You may find this introduction to building your own AR15 of interest.
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