Standard AR15 jigs require modification in order to be used with our BILLET AR9 and AR45 80% lowers.
5D Tactical Router Jig and New Frontier Armory Universal Jig are compatible without modification.
LRBHO AR9 80% Lowers will work with standard AR15 jigs.

AR9 & AR45 80% Jig Modification for Standard AR15 Jig

You can easily modify a standard AR15 80% jig to machine out your AR9 or AR45 80% lower.  

Using a milling machine is preferred, but a hand grinder or Dremel tool will also work.

Basically, you need to make Surface A flush with surface B on the diagram.

Note: your jig will probably not look identical to this, but the concept will work the same.

The only tolerance area will be on the front pin on the left jig plate (C). You will need to try to get as close as you can without machining into the pin. Take light passes and test fit it after each pass.

Once you machine this surface, your jig will be compatible with our AR9 and AR45 80% lowers.

You will still be able to use your jig for AR15 lowers too.

Tuning LRBHO on LE9 Lower Receivers

**As of 2/28/2019, our AR9 Lower Parts Kit now includes a new bolt catch spring that DOES NOT REQUIRE MODIFICATION.

Please contact us if you would like to order just the spring.

Step 1: Remove 2-4 coils (Maximum of 5) from your factory AR15 bolt catch spring BEFORE installing the bolt catch.

Step 2: Make sure bolt hold wire retainer plate is fully seated and secured against receiver. Use a hammer and punch to tap the top of the retainer plate.

Step 3: Test the mechanism using an empty magazine by moving the follower up and down. The wire should actuate the bolt catch enough to hold the bolt open.

If bolt still does not hold open:

SLIGHTLY bend wire TOWARDS magazine follower.

If bolt holds open after every shot:

SLIGHTLY bend wire AWAY from magazine follower

9mm Buffer Info

Standard carbine length (AR15) 3oz. buffers must be used in conjunction with a buffer spacer.

A heavier buffer (8.25oz.) may be needed for non standard ammunition.