The series of letters in the brand and model may be daunting, but behind them is an AR rifle of real merit. The MK4 RCE’s forged M4 upper and AR-15 lower are of carefully machined 7075-16 alloy. Inside there’s a Geissele Automatics SSA two-stage trigger. The Magpul CTR adjustable stock complements an RKM 14 KeyMod free-floating handguard. CMMG gave the stainless, 16-inch, 5.56mm NATO barrel a fast 1-in-7-inch rifling twist and its own nitride-finished muzzle brake. A Picatinny rail runs the length of this rifle. The MK4 RCE is also available in 300 AAC Blackout. Unloaded, the rifle weighs 6.5 pounds. Add a pound if you load the 30-round Magpul magazine. For more information, visit cmmginc.com.