Barrett M99 scope slipping forwards

[omt223]

Loctite, 3 rings, But don't OVER TORQUE the rings...you can crush the internals...one of the first signs of over torque is the parallax gets stiff...next sign....well...it's a good it's not an expensive scope!!!! Good luck....50s are a ton of fun...but definitely present new challenges!.....One other thing..my scope is torqued to 24 inch pounds. .I always check torque before shooting and about every 10 rds....scopes were never designed for FORWARD PULL created by muzzle breaks so they present new challenges to the manufacturers!

I noticed the screws walking out initially with no loctite; blue loctite seemed to fix that but still slid.

 

[skipglo]

I noticed the screws walking out initially with no loctite; blue loctite seemed to fix that but still slid.

Loctite the scope in the rings also. If you don't want to do that...then a single wrap of electricians tape can help!

 

[parshal]

I've used electrical tape as well as little strips of paper with good results. Recently, though, I've taken to bedding the bottom half of the rings with epoxy. I haven't had anything slip since then.

 

[Dragoon300]

Use Badger Ordnance Max 50 rings, you will not have slipping with them.
you can use 3 or 4 rings will help, but they need to be matched as a set, or lapped properly when installed so the bores are all aligned.

 

[Deviant]

I have a M99 in 50 BMG with an Arken SH4 34mm tube. EGW couldnt give me an answer if their keystone rings were up to standard for 50 BMG so they sent me a set in exchange for a review. The arken rings that were "rated for 50" cracked.
Using the torque EGW gave me (15 in-lb) the scope slipped forwards about 1cm after 20 rounds or so. To me, the scope in the rings is SUPER slick compared to most rings I have ever messed with (with the rifle on the bipod and the lower half of the rings only, the scope will slip all the way back to the bell).

They told me I can tighten the screws to 30 in-lb max but that damage to the scope may result. Also stated that a slip of computer paper lining the rings may also provide more surface area.

Any other ideas on what I can do to remedy this without buying a lapping bar?

Dont lap just properly bed your rings. Lots of videos on Youtube and very easy to do. Also if you are using a lead sled or other similar rest that is a scope killer.

 

[Bravo 4]

We never had issues with the M82s. Not sure what those rings were, but they were nothing like these today.

Believe the M107 is issued with 30mm Leupold MK4 rings. Not looking at them but think all 47 I have in my vault has them, and the M107 deployment kit has NSNs for Leupold ring repair parts.

 

[Pro2A]

I have a M99 in 50 BMG with an Arken SH4 34mm tube. EGW couldnt give me an answer if their keystone rings were up to standard for 50 BMG so they sent me a set in exchange for a review. The arken rings that were "rated for 50" cracked.
Using the torque EGW gave me (15 in-lb) the scope slipped forwards about 1cm after 20 rounds or so. To me, the scope in the rings is SUPER slick compared to most rings I have ever messed with (with the rifle on the bipod and the lower half of the rings only, the scope will slip all the way back to the bell).

They told me I can tighten the screws to 30 in-lb max but that damage to the scope may result. Also stated that a slip of computer paper lining the rings may also provide more surface area.

Any other ideas on what I can do to remedy this without buying a lapping bar?

Locktite bearing mount...green, as I recall.

 

[omt223]

Dont lap just properly bed your rings. Lots of videos on Youtube and very easy to do. Also if you are using a lead sled or other similar rest that is a scope killer.

I just looked into this, didnt know it was a thing.
Will probably give that a try

 

[Deviant]

I just looked into this, didnt know it was a thing.
Will probably give that a try

I do it on pretty much all of my rifles anymore because it's so easy to do and works flawlessly. Ryan Pierce built my last rifle for me and he recommended that I do it.

 

[BigDon]

Locktite bearing mount...green, as I recall.

I uses Permatex black gasket compound on mine with great success. Cheap, easily available, comes off easy when you want it to. It's like a much higher quality rubber cement.