A SLIM & COMPACT version of JMac'S ever so popular RRD-4C. The RRD-2C is a shortened version of their popular RRD-4C muzzle brake. The RRD-2C was created by removing the 2 smallest ports from the RRD-4C, creating a more compact package while still maintaining the ability to mitigate recoil. Product Specs: Weight:1.34 Ounces 1/2-36 Threads 10mm Bore 17-4ph Stainless Steel Black Nitride Bore machined for 9mm projectiles Not intended or recommended for barrels shorter than 10.5" if used with rifle calibers When testing these devices with rifle caliber ammunition, JMac found that high rates of fire such as full auto or &ld Mfg: Jmac Customs