Editor’s Note: Daniel Defense's Mk18 runs extremely well. It's a blast to shoot and handled well in CQB-type training scenarios. We've put well over 1,000 rounds through our model, and it's still running like it did day one. We did have a little trouble with DD proprietary mags -- but that was managed by removing a couple of rounds and gently seating it into the magwell. PMAGs run great, though! The Mk18 is a fun pistol or SBR option (depending on what you prefer). Chambered in 5.56 NATO, it offers a 10.3-inch barrel on a 28.6-inch overall length. Pistol versions sport an SB-Tactical pistol stabilizing brace (keep an eye out, though, as laws may be changing there).