I dont know if this is normal or not for larue mounts but when I lock the bolt back and send it home a few times, I notice that the larue mount shifts backwards very very slightly.
I normally push the mount forward in the rail gap when I lock it down and when I remove it I notice the recoil lug is now against rear rail gap instead of the front. Happens with both my T-1 mount and the SPR mount on 2 different uppers. Both are locked down pretty tight.
Just wondering if anyone else noticed this.
hmmm… I have owned/used various Larue mounts and have never experienced this.
If mounted properly, the mount cam will bite into the underside of the rail… movement would be virtually impossible.
Only explanation is that the mount is not adjusted tight enough.
No, trust me its tight. I tested it by tightening to the point where you barely open it with your fingers. I just think people dont notice it. The movement is VERY slight, less than 1/16’s of inch.
I suggest you try it for yourself. Slide the recoil lug forward all the way in the rail notch. Now there should be little ledge at rear of the mount where it meets the rail which you can feel with your fingernail. Lock back your your bolt and let it forward 3 times and feel if the ledge is still there. Both my mounts lose the ledge after releasing the bolt 3 times meaning the mount is sliding back slightly.
LaRue Mount or Mount(s)? Are you saying this about one mount or as your Title says many?
Hmm No my larue lt-150 and fixed larue Buis do not move once clamped down.
Suggest you put another 1/4 turn on the adjustment nut and try again .
Your weapons rail may be out of spec; what make is your rifle? Where did you get your mounts from? The reason I ask is Chicom knock offs of LaRue kit are starting to show up.
this ^
I haven’t noticed anything like this with my LaRue mounts. I’ve owned close to 20 LaRue mounts over the years and currently own 2, a high Aimpoint Micro mount and a LT150 with a C3 in it.
What brand of upper receiver?
I have many and they don’t budge. Post some pics of the rifle and mounts.
I have a LaRue SPR on my rifle and a LaRue Eotech riser on my duty rifle. Neither move at all. Zeros hold perfectly after removing and reattaching the optics for cleaning.
Went and double checked, no such movement in several mount and upper combos.
I tried them both on 2 different uppers and 2 different mounts. 1 is an LMT and another is a rainier arms billet receiver. Both mounts were bought from the larue website. I doubt they are defective in anyway.
They are already pretty hard to remove so Im worried about damaging my rail if I tighten them down more. Anyway I havent really notice any zero shift from it. And honestly the movement is so slightly its barely detectable.
Ill try to get some pics up later.
I’ve got 3 on three different rifles/shotgun. No movement.
I have this with my RASII Aimpoint mount, on a RASII. Was mounted tight enough originally that it took an implement to disengage it from the rifle, like a sling strap, screwdriver blade, etc.
After at least two thousand rounds, maybe three thousand, it now has movement front to back. I think I can re-adjust and lock it back down tight. We’ll see.
Other notable folks have noticed it too, but I will allow them to discuss this if they choose.
Also, I should note that no other LaRue mount I have owned has done this, even on carbines with higher round counts and heavier items – like a Short Dot in an SPR-E.
Anyway I got some pics up.
In this pic, I pushed the mount all the way forward so the recoil lug is pushed against the forward rail gap. Note how you can see the ledge it creates how the letter open catches on it.
Next I lock the bolt back and sent it home twice. Now notice that ledge is gone and the letter opener cant catch on it anymore.
So is it just an issue of me not tightening it enough? Its already tight on to the point where it marred the anodizing off the rail pretty good.
Tightened it down another 1/4 turn. Still occurs.
Why don’t you e-mail Larue with your details and pics and see what they say?
FWIW my Larue T-1 mounts do the same thing. They are adjusted VERY tight.
Because I doubt my mounts are defective in anyway. I have a brand new SPR mount and a older T-1 mount and they both do the same thing on different receivers. I think its just something Ill have to live with. The slight movement probably wont affect zero so w/e, I just wanted to see if this was an isolated incident.