Continuous scope ring slippage

[penguinofsleep]

Update 3/27 see #39 below.

Have a 7RM with a 24.7" barrel and a radial brake on the end. Paired with a Zeiss Conquest v4 6-24x50 and Seekins 30mm rings. Scope will slip literally within 5 shots and slips every 1-2 shots afterwards per shifting POI and the pencil witness marks on my scope moving. Moved about 1-1.5mm in 9 shots.

The scope continuously slips rearwards (toward the butt of the rifle) in the rings regardless of what I do. I sent the scope to Zeiss to confirm that it is not out of round or out of spec - it's not, don't have the measurements they gave me right now, but off the top of my head nothing looked wrong with the numbers.

Info:
Have the torqued to 22in/lb (max per Zeiss when I called them). Torqued in normal star pattern and then torqued again once everything was tight, measured per Borka torque wrench.
Added powdered rosin - didn't help.
Did not alter the inside surface of the rings or the outside surface scope in any way. Also called Seekins for ring warranty and they sent another set - didn't help.
Tried ARC rings as well and had slippage too.
Have a radial brake at the end of the barrel - not sure if the change in recoil impulse is related to this but I've seen bigger rifles with bigger brakes that would induce a "faster and jerkier" recoil impulse (i.e. the jerk function) not have problems with "similar quality" rings.
Am not using a particularly hot load, heavy or light projectiles, etc. - i.e. all well within book limits for projectile weights and velocities.
Scope is not particularly heavy - 24.3oz - not sure if this has to do with anything practically speaking
Don't think it's how I mounted anything - have other rifles, including larger cal, and none have a scope slippage problem this persistent. One other rifle did have a much more minor slippage problem (much less slippage in 50 rounds) but that was resolved with 22in/lb on the rings (up from 19) and powdered rosin.
The rails do not slip in their pic slots and the scope base does not slip either.

Any ideas here or just get different rings? If different rings is the solution, any recs around or under $150ish - would like something not too large / heavy as this is a hunting rifle but don't mind something with a little weight to it. 1 piece mount isn't possible with the rails on this rifle.

 

[Covertnoob5]

Dang that sucks. Usually Seekins is really good. I’ve never had an issue with mine.

As far as other options maybe Hawkins on ARC?

 

[Edsel]

Any ideas here or just get different rings? If different rings is the solution, any recs around or under $150ish - would like something not too large / heavy as this is a hunting rifle but don't mind something with a little weight to it. 1 piece mount isn't possible with the rails on this rifle.

Personal favorite: Badger Ordnance MAX-50 rings.

Might be a bit above $150, though.

 

[TonyAngel]

Man, I don't know. I know that Ssekins makes some good rings and the Zeiss Conquest V4 isn't a cheap line of optics. Have you put a micrometer on the scope tube to compare to other brands of scopes of similar diameter. It wouldn't be the first time that two brands just didn't play well together. The easiest thing to do would be to try a different set of rings.

When you tighten down the ring caps, do you have a gap between the cap and base of the ring?

 

[Aftermath]

You didn't, by chance, lap those rings?

I like the ARC M-BRACE. I like the Eratac stuff, too.

Long ago, we would use a dot of clear lacquer on the bottom ring and set the scope into that before torquing down the screws.

 

[cooper_257]

try some rubber cement in the rings. clean both the scope tube and rings with rubbing alcohol. Apply the rubber cement to the rings. Torque the scope in them and clean up the excess. This worked for me on a 416 Taylor I couldn't get the scope to stay put on until I did this. The rubber cement is also very easy to clean off of the scope and Rings once it is dry if they are ever removed

 

[wpeach1912]

I have a buddy that has had multiple scopes slip and I can’t explain why some do. One of the scopes was a Gen 2 razor in seekins rings on a 300 Norma. He switched to a spur mount with Rosin and that fixed it

 

[Ronws]

I use Vortex Precision Matched rings. About smidge over $150 for a pair. Set and forget.

Amazon.com

 

[wpeach1912]

I use Vortex Precision Matched rings. About smidge over $150 for a pair. Set and forget.

Amazon.com

Those are seekins PMR rings. Seekins makes them for vortex

 

[mildot326]

Try some Rosin, Brownells sells it IIRC

 

[Ronws]

Those are seekins PMR rings. Seekins makes them for vortex

Interesting, I did not know that.

 

[Edsel]

Honestly, if the scope is slipping and you need Rosin to keep it in place - it's probably prudent not to use those rings.

I'm under the impression that this rifle isn't a trash plinker.

 

[hlee]

I have gleaned, while reading Spuhr related threads, that the use of rosin on scope rings is VERY common in Europe.

 

[RubiconJoey]

Have you tried a different torque wrench?

 

[Scott Parks]

Is this on a remington action? If so, have you bedded the base? The back shelf can be low or sometimes high (ive mostly seen low) causing a bow in the pic rail. Bedding will fill that gap and get your rings in alignment.

If you can give us some rifle specs and/or pics we can probably help. If you do have an underlying issue new rings probably are not going to solve your problem.

Best Regards,
Scott

 

[Wade]

Regardless of brand of scope or rings, the first thing I'd confirm is that the ring caps are not contacting the ring bottom halves when torqued.

 

[jbuck88]

That was my thought too. Check the gaps on the ring caps to ring base?

 

[Rob01]

If you have had two sets of rings and it’s still doing it then the issue is not the rings. Seekins makes excellent rings. I started using them in 2005 and never had a set slip even on magnums used in matches. You didn’t lap them did you?

I’d measure that tube again and see if that is the issue. If you are torquing to 22 in/lbs for the cap and it’s moving then something isn’t measuring right. You have another 30mm scope you can put in and try?

 

[penguinofsleep]

Thanks for all the replies.

If it makes a difference, this is a Sako 85 with Contessa scope base. Have another Sako 85 in 300WM, same Seekins rings, and the S/N (of the rings) is 1 after the original pair of rings on this 7RM, same scope base, but with a Vortex LHT 4.5-22. So a little more recoil / force with the same mounting system with a similar weight, size, spec, etc. scope - no slippage ever. The 3rd Sako 85 uses a NEAR mount and I have also used Seekins and ARC rings on that one without issue (granted, smaller caliber).

There is an even gap on both sides of the rings. Rings were not lapped and surfaces were not altered in any way on the rings or the scope.

The most confusing part: I also tried moving the Vortex in it's Seekins rings from the 300WM to this 7RM and the Zeiss in the original Seekins rings to the 300WM, fired about 15 shots on each (no rosin on rings), no slippage. However, for this particular rifle, I want the Zeiss scope on it.

Forgot to mention originally - also tried ARC rings originally with this rifle and that pair of rings slipped too. Sent the rings to ARC, they said they found a minor issue with the first pair, and sent a new pair - so at that point I had wrote everything off as just a bad pair of rings. Still had slippage with the new ARC rings, but it was much less than the first pair and less than the Seekins rings right now. Ended up using those rings elsewhere - no slippage.

And yes, no slippage with my other Seekins, ARC, etc stuff.

Have not tried a different torque wrench as 1) I've used this for a decade+ without issue. and 2) Given how this torque wrench works, I don't know how it would go out of calibration (short of abuse) as torque on it is set by adjusting the length of the arm (r) and not reliant on any internal mechanism that can become uncalibrated (Torque = r * F). For the other part of the equation, force (F) applied is basically two moving parts having to over come each other and looking at the mating surface of the two moving parts (which you can see when you slip them past each other), they do not appear roughed up, worn, or smoothed out / down in any way (i.e. lower/higher F needed to move the parts past each other).

 

[penguinofsleep]

Anyways:
@Scott_at_Vortex - Not sure if this answers anything for you - but this is a laminate pressurized/compressed wood stock from Sako. What you say makes sense so I checked - the fit of this stock to the action is pretty good / close and I did check the scope mounts/bases and rings just now with a machined flat metal block and a .001" feeler gauge - nothing is bowed or warped or twisted with either Contessa base / Seekins rings on either Sako 85.

For $3 I'm going to give the rubber cement a try - pretty familiar with that stuff as I used it a lot as a kid in school. I know it cleans up quite well and I can't imagine it having any kind of electrolytic or other chemical reaction over time between the scope and rings that would damage either one.

@Aftermath - Just want to confirm, for the clear lacquer - you were using it functionally like glue in the middle of the scope ring? And you mentioned long ago - Do you still do this today and how did you remove the scope / rings (i.e. would "just pull hard" deform the scope body at all)?

Otherwise, it seems like most things mentioned above were checked or tested against already. Perhaps it really is just a "this rifle doesn't like this ring" combo. If that still doesn't work... then I guess it's time to try Badger or Hawkins on this. I have other Badger and Hawkins rings, but not ones that will fit here, so I can't just move them over to test right now.

 

[high right]

Schmidt recommends using strips cut from Latex gloves between the scope and rings. Never tried it, but they might know a thing or two.

 

[kl3309]

Try a set of the 6-screw Badgers for more bearing surface. If those are too hard to find, Weaver has 6-screw rings as well, though their's have slotted top caps so you lose some contact there.
I'd try the cheaper Weavers at their recommended torque numbers (either 16 or 18 in-lbs) first to reduce risk of deforming the rings.

 

[Aftermath]

Schmidt recommends using strips cut from Latex gloves between the scope and rings. Never tried it, but they might know a thing or two.

I think there is a recent post in the Motivational Picture Thread about unique uses for condoms....

 

[chevy_man]

Try a set of the 6-screw Badgers for more bearing surface. If those are too hard to find, Weaver has 6-screw rings as well, though their's have slotted top caps so you lose some contact there.
I'd try the cheaper Weavers at their recommended torque numbers (either 16 or 18 in-lbs) first to reduce risk of deforming the rings.

Weaver tactical have the typical torx head screws. Only downside is the nuts on the pic side aren't captured.
I used them a lot on small and cheap stuff when they were $35. Not so often now at $60.

I'm that guy that just uses the "finger tight" method on his rings, never had a set slip or break.


Small torque wrenches are fickle. I'd honestly try 25 in-lb and see if they stop. If the scope crushes between 22 and 25, then 22 was way to much anyways...

 

[6.5SH]

I don't understand how the scope is moving to the rear, it should move forward (towards the muzzle) under recoil.
As an example, some old style externally adjustable scopes had a spring to move them back. Without the spring you have to pull the scope to the rear after each shot.

ETA:
As a related example, you seat the cross-bar or bolt FORWARD against the rib in a Picatinny rail slot to prevent the ring base clamp from slipping.

 

[slodsm]

Completely different setup, but the Burris adjustable rings that have the plastic inserts and 6 bolt caps maybe?

Just about all I use are either ARC rings or Warne Skyline mounts and never have issues but I also don’t shoot any mega magnum calibers either.

I just wonder if the 6 bolt Burris rings meant to adjust scope angle would have a better grip due to the inserts.

 

[terrell35744]

I have had rings slip before it can be caused by many factors but the easy way to fix it is to bed the rings I included an article from Jim See https://www.longrangehunting.com/articles/precision-scope-mounting-for-the-working-rifle.1227/

 

[supercorndogs]

Springers move the scope backwards. Considering the direction of movement. Have you tried it without the brake?

 

[hero's machine]

I will be the odd man and suggest you tighten it up.

Torque is measured by resistance at the fastener head and in a perfect world will reflect tension.

Different thread pitch, pitch diameter, materials and wet/dry all make a difference.

If everything I did was not working, I would think it's probably me.....and it's easy to find out.

 

[Ronws]

I know I have always tightened my ring bases with forward pressure towards the muzzle using the finger on my free hand. Recoil would cause the whole thing to maybe shift.

It still sounds like the Kobayashi Maru, no way to win on this gun the OP is talking about. Which makes one think there is Sum Ting Wong with the top of the receiver.

 

[B y r o n]

Thanks for all the replies.

. . . Have not tried a different torque wrench as 1) I've used this for a decade+ without issue. and 2) Given how this torque wrench works, I don't know how it would go out of calibration (short of abuse) as torque on it is set by adjusting the length of the arm (r) and not reliant on any internal mechanism that can become uncalibrated (Torque = r * F). For the other part of the equation, force (F) applied is basically two moving parts having to over come each other and looking at the mating surface of the two moving parts (which you can see when you slip them past each other), they do not appear roughed up, worn, or smoothed out / down in any way (i.e. lower/higher F needed to move the parts past each other).

With regard to how your torque wrench would come out of adjustment, that would be physical wear on a part or the weakening of a spring. You didn't mention which version you have but the couple I have looked at have a handle/lever at the end that will break over when the torque value is reached. My guess is that detent on the lever is a ball bearing backed by a spring and an adjustable set screw to set tension for the torque break over. Springs can weaken over time or the notch the ball rides in can wear if used a lot.

Shops that use precision torque wrenches usually have a calibration schedule where the wrenches are checked after a certain time or usage limit is reached. That is because as parts wear or weaken, torque values will drop and you will be under the desired torque value. Also, torque wrenches if calibrated usually come with a calibration document showing what their range or error factor is. Most are usually around 4%, usually higher at the lower settings and lower at higher settings.

Try another torque wrench and see if you still have slippage. Think about sending your wrench back in to get re-calibrated or replaced if defective.

 

[cas6969]

I should find some of my old pistol scopes, ones where I "shark toothed" the rings with a punch to keep it from slipping. Worked great... as long as you never want to use the scope on anything else ever again.

 

[Thump_rrr]

I use Vortex Precision Matched rings. About smidge over $150 for a pair. Set and forget.

Amazon.com

Those are seekins PMR rings. Seekins makes them for vortex

That is my go to ring set.
I've paid much more for other rings but don't see the point.
All a set of rings has to do is hold the scope without moving and not damage it.

 

[Ronws]

That is my go to ring set.
I've paid much more for other rings but don't see the point.
All a set of rings has to do is hold the scope without moving and not damage it.

Also, for me, rings are the thing you cannot skimp on. Otherwise, you spend twice as much buy more sets and time to lap them, etcetera.

Jimmy Hamilton said it best. You build up a great car and you should not put cheapie 1 ply tires on it.

Same with whatever scope you use, that price being secondary. Put on good rings and trust it will stay, all other things in this thread being considered.

And I learned something that I have since verified. While Seekins does not make all Vortex rings, they do make the Precision Matched And Precision Extended.

 

[Baron23]

I use Vortex Precision Matched rings. About smidge over $150 for a pair. Set and forget.

Amazon.com

Seekins makes those rings...same/same.

Ooops....lol

 

[Holliday]

That is my go to ring set.
I've paid much more for other rings but don't see the point.
All a set of rings has to do is hold the scope without moving and not damage it.

Same here. I’m planning on selling my Spuhr and going with their one piece on my range rifle too.

 

[jpjulian]

try some rubber cement in the rings. clean both the scope tube and rings with rubbing alcohol. Apply the rubber cement to the rings. Torque the scope in them and clean up the excess. This worked for me on a 416 Taylor I couldn't get the scope to stay put on until I did this. The rubber cement is also very easy to clean off of the scope and Rings once it is dry if they are ever removed

That was the tip Ross Seyfried wrote about some years ago to prevent scope slippage on his big magnum rifles.

 

[JerkyFreak]

Just go old-school and lap those rings. Use engineers blue to check that you have more than 90% contact then you are good to go. This is the correct way to mount a scope.

All other ways using rosin or rubber compound is a shortcut. Those ways work most of the time, but you are never quite sure when the compound breaks down.

 

[penguinofsleep]

So @Scott Parks helped me figure this out back in January but it's been a process to say the least to get this fixed with the manufacturer of the rail and I've been busy with other stuff myself. As of right now, it is still unresolved which I'll get to below. But it looks like there may be an easy enough solution - I would like help from members here w/ regards to the solution:

Problem:
Anyways, it turns out the Contessa rail itself is about 0.002-0.003" too narrow at it's widest point. Just enough so that all of the rings I've tried cannot fully / properly grab onto the scope base. As Scott explained to me, when most rings are fully torqued down, there is supposed to be a small gap between the moving part that clamps the rail and the body of the ring. In this case, when the base of the rings are fully torqued down, there is no gap between the clamp and base of the rings (This means that the ring may not be "fully" grabbing the base as there may not be enough rail for the rings to grab on to. This causes the rings to slip in the pic slot a tiny bit each time the rifle is fired. After some amount of shots fired this also causes the scope to slip backwards towards the butt of the rifle.) Double checked with each of the ring manufacturers that their rings were designed to have a gap when torqued down and all of them confirmed this. After a lot of back and forth I was sent a replacement rail by the rail mfg but it's still too narrow (only 0.001" wider than the defective one in question above) - no gap. The "good rail" from this same rail manufacturer does have a gap with ALL of the same rings that had no gap on the "defective rails". Then, after showing this to Contessa and asking that they measure a replacement rail and then send it to me, they said there isn't anything else they can do to help.

Also, when I ran this by all of the scope ring manufacturers, they also independently told me the same thing as above, most without any further prompting after I mentioned "no gap right now". i.e. This is not just a case of "well I think it works like this".

Possible solutions - please advise if you know something:
1) Most importantly - could I just functionally "shim the rail" or the inside edge of the scope base to effectively "make the rail wider" since I only need a few thou? If so, what product would be recommended here? Don't want to use anything that will slip with recoil, get messed up when exposed to some rain or "not indoors weather", will naturally decay / significantly compress / disintegrate over time, or cause galling or some sort of similar damage via electrolysis over time. Most steel or aluminum foil tapes are too thick (i.e. I imagine the scope base won't be able to clamp properly afterwards). Normal aluminum foil seems like it would cause some sort of galling over time. Shim stock may not stay put over time or under recoil. Any ideas here?

2) If I cannot do the above, is there a known good brand of rings that are not "super heavy" (this is a hunting rifle) that will "always have a gap" even when torqued down with no rail? Or if not an explicit gap, is designed in such a way that it's going to grip regardless? Preferably not over $200 for the rings.

3) There is only one other rail option for this platform that I'm aware of, and they're (relatively) quite expensive, more so if I have to pay additional tariffs on them, so that is the last option I want to take.

Measurements:
The "defective rails" from Contessa measured 0.832" and 0.833" wide at their widest point measured with calipers. When measuring 6 other rails (none of which have problems, including the "good rail" from Contessa), all of them measured 0.836-0.839". Doesn't sound like much but it's enough that all of the rings used here have a noticeable gap on these rails when torqued down. I also measured spare pic rail sections that can be purchased for say MLOK slots and these are also in the same size range or larger. I realize calipers are not the perfect tool for this, but I did take multiple measurements on multiple rails and got the same results each time and I figure in this case it's the relative, not the "absolute", results we are worried about.

Other:
I will not be buying more products from Contessa in the future and while this is not a common platform, if anyone asks, I will mention this experience given the support experience here, even if the products themselves do seem well made otherwise.
OTOH thank you again to Scott for pointing this out. While I have many other Vortex products, not a single Vortex product was in use in this case.

 

[TonyAngel]

I've had this issue, albeit on a .22. Still, trying to shim the sides of the rail is going to be an exercise in patience, if not futility. Just cut an aluminum strip out of a coke can and put it between the bottom of the rings and the top of the rail. If you don't want to use a coke can, you can get strips of stainless shim material from Amazon.

 

[Orion the Hunter]

Just go old-school and lap those rings. Use engineers blue to check that you have more than 90% contact then you are good to go. This is the correct way to mount a scope.

All other ways using rosin or rubber compound is a shortcut. Those ways work most of the time, but you are never quite sure when the compound breaks down.

uhoh... I'm old? When did that happen?
I've not had one move since I learned to use scope align and lap tools. it's just a set of 1inch steel rods with 2 short ones to check ring alingment and one long one for lapping rings. The long one has a threaded handle hole midway down its length. You use valve grinding compound and rub it back and forth while slowly tightening the rings until you get a good contact pattern. I've also found letting a single drop of blue loctite land in the rings helps. Bad mounts happen, but bad rings are pretty standard without this process imo.

 

[JerkyFreak]

Yeah, lapping rings don't happen much these days.

In the last 5 years, none of the people I spoke to at my local range had lapped rings.

 

[Rob01]

Yeah, lapping rings don't happen much these days.

In the last 5 years, none of the people I spoke to at my local range had lapped rings.

And there is a good reason for that. Manufacturing is so much better than 30 years ago when lapping may have been needed. Haven’t lapped a ring in over 20 years and never saw a need especially with Seekins rings.

And I was laughing at his last line as it’s complete BS. Not that he called himself old.

 

[Ronws]

I use Vortex Match Precision rings and never lapped them. A bit pricey, yes, but set and forget.

 

[Orion the Hunter]

Now now...that wasn't very nice. I did mention I may be outdated by your standards, but if this is how you treat new members I guess I'll have to take the high ground and not waste my time here.
Also. um.. The OP seems to have a problem, I was only trying to help. And yes, I was punching paper before you were born.

 

[spife7980]

Now now...that wasn't very nice. I did mention I may be outdated by your standards, but if this is how you treat new members I guess I'll have to take the high ground and not waste my time here.
Also. um.. The OP seems to have a problem, I was only trying to help. And yes, I was punching paper before you were born.
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