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Scope shifting under magnum recoil - solution?

penguinofsleep

Sergeant of the Hide
Full Member
Minuteman
Nov 26, 2020
120
27
Somewhere USA
Background and Problem:
Have two Sako 85 - both in long action magnum calibers (300 and 7mm) with no brake / muzzle device.

Currently using Leupold QR rings (SKU 49933) with only 1 screw on each side of each ring and not too surprisingly to me, the scope shifts back towards the buttpad a fraction of a mm after each shot causing a drifting zero. However, as far as I know, these particular Leupold QR rings with the corresponding Leupold base and the Sako Optilock base + rings are the only options for the S85 that gets the scope high enough over the ejection port to where an occasional (~10%) shell that gets flipped upwards instead of out sideways (the Achilles heel of the long action S85 due to the ejector position) will still properly eject and not cause feeding issues.

Question:
Is there anything that can be done to help hold the scope in the rings that doesn't involve changing to wider rings with a scope base or having wider rings custom made that work with the corresponding base?

I see online that some people put blue loctite between the rings and scope rings for additional grip, but because it's an aluminum scope and steel rings here, I imagine that this could cause galling (electrolysis) over time. Is there something similar to teflon tape that would be gripper or better than teflon tape would be in this application?

Other Info:
Currently have the rings at 27in/lb and the scope ring screws have blue loctite. Even after the scopes shift backwards on both rifles, when I checked the screws they were still tight and the loctite on the screws had not broken upon initial loosening by me. The bases also remained tight and did not shift. I cannot move the scopes in the rings at all using my hands as expected. I have not tried lapping yet but I don't know if this would help as the rings just aren't that big.

I've read at various places online that the same Leupold ring setup mentioned above has worked for people with larger caliber Sako 85 rifles (ex XL action safari calibers) without issue. Don't want bigger rings as that would require a scope base which would mess with the ejection port clearance issue above. Went through 4 sets of Sako optilock bases and none of which fit properly on my particular rifles (this was confirmed with Beretta techs to make sure it wasn't me imaging it after the 2nd base - they were surprised too). Not interested tossing the rifles or adding a brake right now as these are amongst the very few firearms that I actually want as a collectors item first and to shoot second.

No idea why Leupold doesn't just make the rings a little wider and use 2 or more screws on each side like they do with most their other rings I see......
 
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Check alignment first. Your scope should slide between the rings very smoothly with the ring caps off. I would then bed the ring bottoms with your choice of bedding compound (jb weld, devcon, marine Tex, etc). Just put release agent on the scope, put bedding compound on bottom rings, and barely torque the screws with the scope installed. Clean up excess bedding with a Q tip and some WD40 before it hardens.
 
Actually that would probably work.

If that still doesn't do it, will probably just deal with a scope rail so bigger rings can be used.
 
Get rid of those trash ass rings. Talk to Murphy and get a rail made for it to use a real scope mount (badger, ARC, area419)

 
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Background and Problem:
Have two Sako 85 - both in long action magnum calibers (300 and 7mm) with no brake / muzzle device.

Currently using Leupold QR rings (SKU 49933) with only 1 screw on each side of each ring and not too surprisingly to me, the scope shifts back towards the buttpad a fraction of a mm after each shot causing a drifting zero. However, as far as I know, these particular Leupold QR rings with the corresponding Leupold base and the Sako Optilock base + rings are the only options for the S85 that gets the scope high enough over the ejection port to where an occasional (~10%) shell that gets flipped upwards instead of out sideways (the Achilles heel of the long action S85 due to the ejector position) will still properly eject and not cause feeding issues.

Question:
Is there anything that can be done to help hold the scope in the rings that doesn't involve changing to wider rings with a scope base or having wider rings custom made that work with the corresponding base?

I see online that some people put blue loctite between the rings and scope rings for additional grip, but because it's an aluminum scope and steel rings here, I imagine that this could cause galling (electrolysis) over time. Is there something similar to teflon tape that would be gripper or better than teflon tape would be in this application?

Other Info:
Currently have the rings at 27in/lb and the scope ring screws have blue loctite. Even after the scopes shift backwards on both rifles, when I checked the screws they were still tight and the loctite on the screws had not broken upon initial loosening by me. The bases also remained tight and did not shift. I cannot move the scopes in the rings at all using my hands as expected. I have not tried lapping yet but I don't know if this would help as the rings just aren't that big.

I've read at various places online that the same Leupold ring setup mentioned above has worked for people with larger caliber Sako 85 rifles (ex XL action safari calibers) without issue. Don't want bigger rings as that would require a scope base which would mess with the ejection port clearance issue above. Went through 4 sets of Sako optilock bases and none of which fit properly on my particular rifles (this was confirmed with Beretta techs to make sure it wasn't me imaging it after the 2nd base - they were surprised too). Not interested tossing the rifles or adding a brake right now as these are amongst the very few firearms that I actually want as a collectors item first and to shoot second.

No idea why Leupold doesn't just make the rings a little wider and use 2 or more screws on each side like they do with most their other rings I see......
Get better rings and a better pic rail...Leupold shit sucks and hasn't been relevant in 20 years.

Get a set of the new ARC M-Brace rings, and an EGW HD rail.
 
I had a Kahles slipping inside a set of arc m10 rings and everything was properly torqued. It was on a 10# 338 rum with a big brake. I ended up moving the front ring out a bit, and sliding the bell of objective upto the taper on the front side the ring. This way the scope couldn't slip back anymore in the rings. Ted from ARC actually told me to do this after a talk. Sometimes some rosin may be needed, or the rings will need bedded.
 
One last update for anyone else who may stumble into this thread in the future.
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The Sako factory option was loose in the rear. Literally the scope would be the bridge that actually kept the rear tight... bad idea IMO. Refunded.

The Leupold option above didn't work out as described above. 0 problems with the bases, only problem was the ring just needs more surface area and 4 or 6 screws, not 2... again, no clue why they won't make it for their QR rings... they make it in their other product lines.
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Murphy Precision does not make rails for the Sako 85 due to their machine being unable to perform one of the manufacturing operations necessary for the 85 rail that is not necessary on some other Sako rifles.

Similarly, EGW and several other companies making similar products do not make S85 compatible rails.
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NEAR makes a great base, probably the nicest base I've seen before, but it's relatively expensive (1 base was $275 shipped from Canada to the US). Of note though, and Mr. Near noted this himself as well - his bases sit relatively low meaning that they may not offer enough clearance for shells shell ejected from a long action 85 as shells will occasionally to always kick upwards - it depends on your particular rifle (keeping the mag loaded when ejecting helps). Not an issue with M, S, and XS action (which I use the NEAR base on). The edges are trimmed away on the left and right side to allow easier top loading for a left or right handed action (but not enough to alleviate the ejection issue described).

Got the Contessa rail. They have 2 designs but they seem to be the same part number between the two designs... not sure why they do this. Some are one piece rail + dovetail bases and these bases have an extra clamp on the side of the dovetail to help keep it secure. Others have separate dovetail bases and rails that screw into the dovetail bases... These rails sit high enough that the issue with occasional 85 ejection upwards on a long action shouldn't be an issue. Granted, you could also cut away a part of the rail to give it a little more clearance and to allow easier top loading as well.
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Why deal with all of this when so many other platforms don't have this issue? No logical reason, I just like the rifles.
 
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I've used Burris Signature XTR rings and Signature ZEE rings (with posalign offset inserts) and had absolutely zero movement including use on a 50 BMG that gone through a hell of a lot of rounds.