My scope/mounts slipped at the range Friday.    That makes the third time in the last 200 rounds.    308 Savage model 10 with Weaver scope base and SWFA rings, both aluminum.  When I took it all apart, I found plenty of Locktite in the threads.    No screws were finger loose.     Scope base to receiver had lowest torque to remove screws - 15 in lb., which according to some sources is the recommended torque for that application.   On the rings, the lowest torque to remove screws was 20 in lb, highest 35 in lb.    No evidence of slippage except point on impact drifting 3 moa at 100 yards over the course of shooting 50 rounds.

I cleaned all the threads and will re-assemble with fresh Locktite.     But this is getting old.    Am I missing something?  BTW, using a SWFA SS 10x42 scope.    Could problem be internal to scope?   These scopes have a reputation to being durable.

Sounds to me like your rings might need to be lapped.  Or (please don't be insulted...) they're the wrong size.

Also, are you sure the POI isn't moving for some other reason - like barrel heating?

Use brake cleaner on the rings and scope tube and try again.

I don't use loctite and have over 550 rounds on my AIAT with a Gen II Razor without issues.

I have never re-torqued rings/bases and have never had issues.

What did your initial tracking test show? If there is an internal problem causing POI shift it should have issues tracking. A simple but imperfect check would be to mount it solid as you can, look through the scope, focus on a small object and crank the turrets up and down. Watch that the reticle moves with every click and returns to your zeroed object.


You found nothing loose?

Does the base sit flat on the action?

Has the barrel been fluted?

How does the action mate to the stock?

How far are your rings from the turrets and parallax adjustment?

Is the POI shift consistent? To the same point, say 3moa high at 50 shots and stays there for 60 and 70 shots or is it all over?

You say 3rd time in the last 200 rounds, is this the first 200rounds through the rifle or was there a time before that it didn't do this?

Not doing rapid fire.   about a minute between rounds

Does the base sit flat on the action?      Bottom of base is contoured to match top of receiver.    Appears to be a good fit.

Has the barrel been fluted?     No

How does the action mate to the stock?     Factory stock, but I have had issues with action screws.     There were checked before trip to range.

How far are your rings from the turrets and parallax adjustment?     Front ring 1.5" in front of turret.    Rear ring .75" behind turret.

Is the POI shift consistent? To the same point, say 3moa high at 50 shots and stays there for 60 and 70 shots or is it all over?   I shot 5 round groups, ten groups,  50 total.     I could watch each successive group drop a little from previous group.    

You say 3rd time in the last 200 rounds, is this the first 200rounds through the rifle or was there a time before that it didn't do this?
First time at 525 rounds,  second time 642,    Now third time at 715.

I did find the scope base front screws about half the torque of the rear screws (15 vs 30 in. Lb.)    But 15 in lb is what some sources say is the correct torque for mounting scope bases.     Could the difference in torque allow the front of the base to slightly rise?   That is directionally correct for a POI drop.

I had a similar issue a while back and after lapping the rings the problem went away and never returned.  Since then I have always lapped and never has an issue.

I have never lapped a set of rings but my ring list has been:
1 X Seekins
5 X Badger
2 X Nightforce
1 X ARC M10

I don't believe lapping good quality rings is necessary or even a good idea personally.

As long as they were tight it shouldn't have an effect.
I bed my bases to the actions always because the match will never be perfect but it doesn't sound like your problem.

I would check the tracking on the scope to see if it repeats and I would put another scope on it to see what happens.

thanks for all your inputs.     I've remounted the rings and scope.    I'll report on the outcome.

The ones I had an issue with were Badger steel rings.  I have used 2 Badgers, 1 Nightforce, and a cheap SFWA set.  Most may not need it but a light lapping doesn't hurt and shows how true some matched sets really are.

Well, this is akward.    I decided to verify the screw size and order some back up parts.    In doing so, one of the ring mounting bolts snapped (during removal ???).   New rings needed now.   So now I've decided to upgrade to steel rings and base.  Hopefully, this will end this slipping problem.

The never ending story continues.

I always put the lapping bar in the rings as a verification and/or a slight touch with 800 grit paste.

Once I get the blue locktite on and torque, I don't touch the screws again.  Seems like it would defeat the purpose of the locktite.

Well, I scrapped the original aluminum base and rings.    Got some steel Leupold components from MidwayUSA.     Installed them using a F.A.T. wrench and loctite.

Went to the range yesterday and the POI dropping continued.     Over 20 rounds the POI dropped 4 inches at 100 yards.   Other than the drop, the grouping was kinda ok.     You could see virtually every single shot was lower than the preceeding shot.

So, this morning I called SWFA.   They gave me a number to return the scope and they would take a look at it.

the never ending story.

I have been through this. Lap the rings, and put a light dusting of rosin on the inside of the rings when you mount the scope.

ETA: just read the update. Hopefully it's just the scope and they replace it. I would still do the above when mounting the replacement