Geissele 13.5" M-LOK MK16 Black Super Modular Rail 05-650B

The Geissele 13.5 Handguard 05-650B sits right in the middle of the MK16 lineup - long enough to give a mid-length or rifle-length gas system full clearance and enough M-LOK real estate for a serious accessory load, without pushing into the weight and bulk of the full 15" option.

This Geissele SMR MK16 is machined from 7000-series aircraft aluminum and locks to the upper receiver through Geissele's proprietary barrel nut, which extends contact with the receiver well beyond a standard nut's footprint. Anti-rotation tabs and set screws reinforce that connection, so the rail holds its position under recoil instead of walking a mounted light or optic off zero over time. A full-length M1913 Picatinny top rail runs the entire 13.5" span for uninterrupted optic mounting, while M-LOK slots across every quadrant give builders flexibility on where lights, grips, and slings actually sit.

Finished in a tough black hardcoat anodized coating, this MK16 handguard stays lightweight without giving up the rigidity that separates a Geissele Super Modular Rail MK16 from a standard aftermarket free-float tube. The same length is also offered in Desert Dirt Color for builds that call for a coordinated earth-tone profile.

Key Features:

• 13.5" free-float length, full-length Picatinny top rail
• M-LOK attachment slots across every quadrant
• 7000-series aircraft aluminum construction
• Black hardcoat anodized finish
• Proprietary Geissele barrel nut for extended receiver contact
• Anti-rotation tabs and set screws prevent rail rotation
• Lightweight design without reduced rigidity
• Fits standard mil-spec AR-15 upper receivers

05-650B delivers the same URG-I-proven rigidity as Geissele's shorter and longer rails, in a length built for shooters who need both accessory space and manageable weight in one package.