The Underworld Arms Aug M-Lok handguard is 5.5" long and is machined from T6-6061 with a black anodized finish. The handguard includes a black oxide 304 SS locking nut and a black oxide 304 SS mounting nut.
When installed the quick change barrel feature is still functional and gas adjustment is accessible.
The UA Aug M-Lok handguard mounts to the barrel using our proprietary hybrid method that takes inspiration from an AR15 style barrel nut and the Aug's locking flash hider nut.
This 5.5" Aug handguard is designed for standard 16" barrels however we are currently machining a run of longer handguards made for the classic 20" barrels.
To install the handguard remove your muzzle device, degrease your bayonet lug threads and the mounting nuts to remove all oils, apply rocksett or a similar threadlocker to your bayonet lug threads, thread on the square locking nut with the unthreaded ID facing the receiver, thread on the wing shaped mounting nut with the wing side facing the receiver, orient the flats of the mounting nut at the 12 o-clock and 6 o-clock and tighten the nuts together, slide your handguard on and attach it to the mounting nut with the included screws. Be sure to use your choice of thread locker on the screws so they do not back out.
Inside Diameter- 1.52"