The AR15A2 Project: Larue 12.0

The AR15A2 Project: Larue 12.0

The Larue 12.0 rail is considered a “classic” rail. It isn’t the most modern, or the lightest, but quality…  absolutely 100% yes.  Larue 12.0 Rail A2 Rifle

The Larue 12.0 is set to be a part of my AR15A2 project. I decided to add a few upgrades to bring my A2 up to speed so I can use it at both CMP matches and Tactical Rifle matches this year and onward. As of right now, CMP legal rails need to be of a certain diameter and feature four picatinny rails at 12, 3, 6, and 9 o’clock. No key-mod allowed yet folks.

While the quad rail style might be going out of style, the Larue 12.0 accomplishes two goals: it is CMP legal based on the measurements given to me by Larue Tactical, and it free floats my barrel.

The thing that strikes me about the Larue is how precise it is. You can observe the quality of the machining. Take a look at this article hosted on and look where the author compares the Larue rail vs the competitors. Pretty striking. While that precision won’t affect the shooting I am going to be doing, it is nice to know you are getting something that was built by someone obsessed with getting things right.

Larue 12.0

Installation was like many other rails. Pound out the taper pins at the front sight base, slide end cap assembly and barrel nut down barrel. Torque until the next gas hole lines up. Install rail. Lock in place with end cap and anti-rotation assembly. Re-install front sight base. If you have a workbench, some punches, a vice, and a hammer… you can install a rail. Make sure the barrel is immobile before you pound the taper pins out.

I was advised by a member of a certain government-funded shooting team that a *very popular* rail system on the market tends to break under sling tension. I was informed that the mounting system has been a failure point on this particular rail. I decided that the way to play it safe would be to go with an older “tube” based rail.

Wrapping Up

Snatching up quality used gear should be second nature. While the 12.0 is an older rail… CIRCA 2004… the quality is there. Don’t be afraid to get good “old” gear cheap on equipment exchanges. Let other people do the beta testing of the new stuff.

Whats next for the AR15A2 project?

  • I need a sling swivel to get the sling off the barrel and on to the FF rail.
  • National Match Rear Sights
  • Match Trigger

Then it’s time to play ball.

Written by lothaen


  1. Matt in K.C. · March 3, 2014

    Any tips as to which *very popular* rail systems might be good to steer clear of, just so we don’t waste money on something that might break just when we really need it?


  2. E.D.M. · March 4, 2014

    Was this “very popular” rail a Troy? I had heard of issues with their mounting, which prompted a redesign for the newest rails. But not sure, since this project wouldn’t be using a Troy tube, anyway.

    I want to do a similar project, but I as leaning towards a Centurion C4. I don’t know if that is CMP legal, though.

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