Aug M-Lok Handguard With Top Rail

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  • Regular price $139.99

The Underworld Arms Aug M-Lok handguard is 5.5" long and is machined from T6-6061 with a black anodized finish and includes a top rail for extending the iron sight radius. The handguard includes a black oxide 304 SS locking nut, a black oxide 304 SS mounting nut, and a black polymer centering plug for use during install. 

When installed the quick change barrel feature is functional and gas adjustment is accessible, the original grip can be left on or removed. 

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. 

To convert this handguard into a quad rail CQC clone see our rail kit availble here

This 5.5" Aug handguard is designed for standard 16" barrels, if you have a 20in barrel you will need to wait for our longer handguard to be released. 

This handguard will fit on A1, A2 and A3 rail receivers, it is not compatible with A3 receivers with a factory scope but we are working on a compatible rail for that model.


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 8-32 screws. Be sure to use your choice of thread locker on the screws so they do not back out. Test the barrel's quick detach function, if the handguard rail engages the receiver then unthread your mounting nut a half rotation. 

Rocksett has a 24 hour setup time, you do not need to rush the process there is plenty of time to line everything up perfectly. 

Included in the box is a black polymer centering plug that lines up the handguard with the barrel, this does not have to be used during installation but it does make squaring the handguard with the barrel easier and faster. If you chose to use the delrin plug for your installation remember to remove it after you are done. 


Length- 5.5"

Width- 1.7"

Inside Diameter- 1.52"

Weight- 5.8oz

Suppressor and quick mount compatibility:

Any direct thread suppressor 1.5" or less will fit, quick mounts needs to be 1.5" or less to fit. Keymo mounts fit, OSS/Huxworks require the extended flash hider, RC2 are too large. We will update this compatibility list as we receive more feedback from customers. 

Customer Reviews

Based on 5 reviews
Matthew K.
Awesome piece for a great price

Rail was easy to install and feels very sturdy. Good price for an AUG rail, shipped quick too . 10/10 would recommend

Conner McQuiston
Easy enough to install

I enjoy firearms and can take them apart fine and dandy but never have I done any modification work on any. This was easy enough to install when you get the muzzle device off finally. The instructions were confusing until I had the pieces in front of me, and it all goes together perfectly. It just makes sense. With the CQC rail kit, it makes the Aug look sick. The machining for all these pieces is excellent, very high quality stuff.

Jacob Hosman
The obtainable AUG CQC

Installation was pretty easy. I recommend doing a test install just to get a feel for getting alignment properly. I couldn't ask for a better looking set up with a rock solid feel and lock up. 100% would recommend to others.

Awesome Product!

Mounted perfect on my 16” and the instructions for installation were easy to follow. Gave me plenty of space to mount my accessories, and doesn’t wobble loose when firing.

Nice Handguard

Easy install, Fits Nice, Makes AUG way more comfortable to control.