Maxim Defense MXM48064 DS-K D 5.56 NATO 1.75" Black Titanium/Stainless Steel

The DS is recommended when not running anything below a 10.3 barrel. Plus, its rated for full-auto shooting. The main differences from the DSX are the absence of the secondary tube retention ring and the use of Grade 9 titanium on the tube instead of Grade 5. Grade 5 titanium is much more expensive, and it simply isn't needed in the DS series.