Adjusting LaRue Tactical Locking Levers
video version, for the reading-impaired
Unload and check firearm before proceeding.

LaRue locking levers are adjustable in infinite increments to accommodate any MIL-STD-1913 (Picatinny) rail, even those that are worn, or out of spec.

Properly adjusted, the mount and optic will be fully-snug on the rail (you should not be able to move or “rock” the optic and mount). The tension on the locking lever is adjustable with very slight movement of the locknut, using the supplied 3/8 inch wrench.

The locknut requires only SLIGHT MOVEMENT to adjust tension. Turning the locknut clockwise makes it more difficult to remove the mount. Turning the locknut counterclockwise makes removal easier. (Never completely remove the locknut)

To adjust the lever’s tension:

1. Place mount and optic on the firearm, in your desired location. Move to another lug space if necessary to get proper cheek-weld and eye-relief.

2. Rotate lever(s) into locking position.
a. If they can’t fully seat, rotate the locking-nut counterclockwise, until closing it requires some effort to fully seat the lever.
b. If the lever swings too easily, rotate the locking-nut clockwise, until closing it requires some effort to fully seat the lever.



As a general rule, adjust the tension until the lever is at a 45° angle when it makes first contact with the rail, then requires about 8-10 pounds of pressure to fully seat (about the same amount of pressure as pushing a thumbtack into dense drywall).

Remember, NEVER EVER completely remove the locknut!

3. With levers locked, firmly hold the optic firmly with one hand, and the firearm in the other, then try to slide optic forward,  reverse and rotate on the rail.

4. If the optic moves, slightly rotate the locking-nut clockwise until movement stops.

5. Now that you’ve adjusted the mount’s tension, mount the optic and zero the firearm as per optics’ instructions. Remove and reattach on same lug space then confirm zero.

6. If the optic does not return to zero, increase tension on the locking nuts very slightly, and try again.

The Locking Slider:
The Locking Slider keeps the lever from accendentally opening
The Slider slides parallel to the mount.  forward to lock and back to unlock (If it’s forward, DO NOT ATTEMPT to PRY the lever OPEN, it’ll damage the mount)

Have you seen my dog???

that makes it a no brainer...great tutorial

I've often wondered, just what happens if you DO completely remove the nut?

The LT Tac Team comes and shoots your dog?  Lifetime ban from future LT purchases?  The Dillo Repo Team comes and snatches up all your dillos?

It's the same as dividing by 0.  The universe implodes upon itself.

Nice write-up, stickify it!

This should be tacked

I actually put it in here...Link

Thanks, but now my wife is mad about all of the thumbtacks I just put in the wall calibrating my thumb.  

Seriously though, great write-up.

^^^
funny!

You need one of these kits:

...off to order one.

http://stores.homestead.com/Laruetactical/Detail.bok?no=496

After reading this I got curious picked up the stealth grabbed the aimpoint and sure enough there was a slight fore and aft movement tightened the nut a little checked for movement had none,removed aimpoint and replaced applied 9.6 thumb pounds of pressure to the lever locking it and checked, no movement.

mfingar your a genius

I have a SIG 522 that appears to have an out of spec rail - it mics out at 0.818" instead of the spec 0.835".  Can a LaRue mount be adjusted down this far?  What about an earlier LaRue mount, one without the locking slider?

Halp?

Try calling them. They can give you an answer in a jiffy

No need - the used mount arrived today.  I was able to adjust it down far enough, but it was close!

We figured in quite a bit of travel for the obscenely out-of-spec ...  glad yours fell in the window.

ML

Thanks, Mark - and this one was w-a-y out of spec!  Nice and solid now.

Thanks.  I just discovered my eotech mount and BUIS both had fore/aft movement. I thought the lever were tight enough. I guess not.

Okay, 6-months ago I tightened all my LaRue mounts per the above instructions.

Today i noticed my BUIS and RASII aimpoint mount were loose again. Ive fired about 1,200 rounds in that time frame.  What am I doing wrong?

I've noticed on my SCAR 16 with M68 CCO mount I still have movement fore and aft with the nut tightened as tight as it will go.  I even  have to loosen up the nut to swing the lever out. Any ideas what I could do to correct this problem?
 

Those locking levers are awesome bits of engineering.  I'd dare say they're aerospace grade.



My SPR's scope has a LaRue mount and it holds zero like nobody's business.  The mount-to-mount error

is smaller than the average group.

Thanks,

Aerospace quality for blacksmith prices.

It's somewheres in the range of .060"-.085" ... at a 100 yds.  

When I joined the Marine Corps and got to the fleet, my seniors told me how crappy the larue mounts were and that if I took the optics off I would lose my BZO. I got my ass handed to me after showing them how to properly adjust the throw levers and tactfully informing my seniors that they were morons

I have an Acog mount that is super hard to tighten the locknut but I have a 1" ring set that's easy to tighten. Why would one be hard to do? Both are set at about the same tension as far as the throw levers go. They both hold zero as well. I have always adjusted the tension while they are clamped on the rail. Should you remove the optic if you are tightening the locknut or can you do it while it's mounted on the firearm?

On the same rail? Some rails have different specs or coatings can affect it. If this is on the same rifle then it's odd.

the locknut is just hard to tighten. I have to hold the lever down and crank with the supplied wrench to budge it at all. The scope does not move so it should be gtg.
Second question. Would tightening it slightly more affect the zero I already have on it. It did not move from its rail slot just got a bit tighter.

Thanks for this. Just had to use this to mount my new to me NF optic. Amazing, of three different AR's, only one would lock until I loosened the nut little.

Seems I always have to tighten them a bunch. The mounts always rock back and forth on the rail tell I do.

Yes.

My lower finally came in and I'm waiting on my scope to ship from Optics Planet.  I took off my Leupold Mark4 off my AR15 to put it on the Larue for a quick photo.  The mount was super tight and I didn't want to mess up the cerakote on the Larue so I put some witness marks on the lock nuts and loosened it up a bit.

I took the photo and mounted the scope back on my AR15 after aligning the witness marks again.

I don't know how much it ended up shifting, but I wasn't able to hit half size silhouettes at 200 yards.

The day was a clusterfuck for the most part.  I forgot my paper targets and the sun was in my eyes so I had a hard time seeing my impacts.  I sighted in by aiming at the top/bottom/left/right sides of the steel and seeing when it would hit, then I adjusted till I was consistent.  It was good enough for plinking and I'll go back next week and zero it properly.

If I had to guess, I'd say that I lost about 6 moa.

I doubt you'll have such drastic changes, but I'd be surprised if you didn't have to dial it in a little bit.