Rifle Scopes Why is my scope slipping in my rings?

[m1ajunkie]

Went out again today to check my gear over once again for Mammoth and found my scope has slid forward in my rings roughly an 1/8". I noticed between checking zero last week and checking today my poi had moved up .1 mil in the exact same conditions. Checked my dope out to 700yds with what was my "new" zero and everything checked out, rifle still shot great groups and the dope tracked dead on.

I get home and find the pencil marks I have on my scope tube to check for slippage indeed show the scope has slipped, and I assume caused this zero shift.

Scope is a leupold MK4 34mm with m5a2 turret in NF ultralight rings. I mounted this up the same way I have done with many other scopes but never had this issue until today. One other note, I have never used anything but badger rings until this setup.

Am I good to simply remount my scope, or should I go back to badgers that have never given me issues?

Who has the 1" high 34mm badgers (non usmc) in stock that could get them out asap? At this point I am afraid I won't be confident again until I put badgers back on.

Thanks

 

[LRRPF52]

Did you lap the rings by any chance?

Are you blue Loc-titing your rings?

Are you using a torque driver for the fasteners to ensure uniform torque settings? (inch pounds, not foot pounds)

 

[DirtyRod]

You shouldn't NEED to lap NF rings if you are tightening to the correct torque settings but you may have to if they aren't holding the scope tightly. I'd definitely verify and use locktite as recommended above if you are not already.

 

[m1ajunkie]

I did not lap these rings and I have never done so in the past, the ring caps were mounted with blue loctite.

At this point I am not sure if I should pull the scope and retorque the caps again or try something different. It has taken probably 500 rounds for the scope to slip so I am guessing something loosened, but I haven't had a chance to check it out in depth yet. My only concern is I won't be able to put another 500 rounds through the rifle before mammoth so I will still have concern in the back of my mind.

 

[XTR]

The only scope I've ever had slip was one that I didn't take the time to torque the screws with a torque wrench.

 

[scudzuki]

Remove the scope and re-mount it after applying a dusting of powdered rosin where it is clamped by the rings.
Torque the ring screws to 20 inch-pounds then check the ring torque periodically.

Joe

 

[6brshooter]

Did u clean the oil off of the ring screws and threaded holes? I had an ior 35 mm that could only be torqued to 12 in/lbs. It was a heavy scope and slid. Ended up putting a drop of blue loctite inside the ring halves and spread around with my finger. That solved the problem.

 

[diverdon]

Remove the scope and re-mount it after applying a dusting of powdered rosin where it is clamped by the rings.
Torque the ring screws to 20 inch-pounds then check the ring torque periodically.

Joe

+1

You don't need the expensive stuff from Brownells just get some from ebay for 2.99 Rawlings Powdered Rosin Bag | eBay

 

[shovelstrokeed]

I have to assume, in this day and age, that any quality ring manufacturer is capable of machining a set of rings to correct bore diameter.
Pretty much the same for scope tubes.
A micrometer and, if you can borrow one, a bore gauge, will tell the story. If you are careful, a snap gauge and the micrometer can do the same job. You want a very small interference fit between ring bore and scope tube.
A bit harder to measure on the rings as they will need to be made up to measure their bore diameter and that will require they be shimmed a specific amount (designer determines how much).

Probably the easy way is to measure how much gap is in the rings when torqued to specification on the scope tube. Use the thin feeler gauges that used to be used for setting points on a distributer back when such things were used. Properly torqued they should have equal gap of at least a couple thousandths on each side. Gap on both sides is important. If the rings are bottomed on one side you will lose a lot of clamping force.

Ooorrrr, just use rosin as has been suggested earlier.

 

[ShtrRdy]

How about just re-torqueing the rings to see if the screws loosend up?

 

[918v]

I have to assume, in this day and age, that any quality ring manufacturer is capable of machining a set of rings to correct bore diameter.
Pretty much the same for scope tubes.
A micrometer and, if you can borrow one, a bore gauge, will tell the story. If you are careful, a snap gauge and the micrometer can do the same job. You want a very small interference fit between ring bore and scope tube.
A bit harder to measure on the rings as they will need to be made up to measure their bore diameter and that will require they be shimmed a specific amount (designer determines how much).

Probably the easy way is to measure how much gap is in the rings when torqued to specification on the scope tube. Use the thin feeler gauges that used to be used for setting points on a distributer back when such things were used. Properly torqued they should have equal gap of at least a couple thousandths on each side. Gap on both sides is important. If the rings are bottomed on one side you will lose a lot of clamping force.

Ooorrrr, just use rosin as has been suggested earlier.

I disagree with your assumptions and the interference fit statement. Never had slipping issue in lapped or unlapped rings where the scope slid freely in the ring bores. I used the l-wrench supplied with the rings and tightened the screws using the long part of the wrench for leverage. If you use the short end, you will never get the screws tight enough. Use the short end for turret set screws, not the ring screws.

 

[shovelstrokeed]

Disagree all you wish, that is what the forum is for.
But even a line on line fit, where the bore of the rings exactly equals the OD of the scope tube will provide no clamping force. You must have a gap between the ring parts when they are assembled on the scope and it is important to retain a gap, ideally in equal parts, when torquing the ring screws. I mentioned nothing about using whatever wrench and which end. I use a calibrated torque wrench on both ring and base mounting screws.

I'll agree the scope should slip freely in the ring bores and that is one of the reasons I stick with Spuhr mounts for all the guns on which I can use them. Rings and base are machined as one piece and I eliminate the vagaries of rail machining from the equation or any need for lapping.

 

[918v]

I never said one did not need gaps between the ring halves. What I disagreed with you about was your assumption that rings are always machined to spec and that you need an interference fit between the scope tube and the ring. That is a recipe for dented main tubes and stress induced mechanical problems. What is needed is a perfect bind free fit so that the clamping power of the rings does not induce any stress.

 

[m1ajunkie]

How about just re-torqueing the rings to see if the screws loosend up?

I checked this and none of the screws were loose. To be safe I am simply going to buy another torque wrench tomorrow and remount the scope.

The rosin sounds to be something to try, do any of you know where I may find this locally?

 

[918v]

Rosin is not needed.

Have you tried the L-wrench or ate you just stuck on that torque wrench thing.

 

[Spuhr]

1. Ringscrews should be greased or loctited to prevent to high friction betwen screw and ring.
Torque is not an exact science as its so dependent on friction and friction is dependent on grease/dry , temperature, material etc.
That is why greasing is recomended but there is quite a number Of users who degreses their screws making the friction and torque high but the clamping force Of the ring low.

2. Rosin cost very little!
Really extremely little but it rises the friction betwen scope and ring considerably. Rosin also acts like a protective cover on The scope against The ring and help you avoiding cutting value down on you'r expensive scopes.

3. Normally with quality rings are not lapping needed. If The picatinny is straight!!!!
If The picatinny not is straight ( not uncommon) then there is no chance in The world that The unlapped rings can compensate for it.

 

[Hammer47]

Had the same problem and the fix was easy. Just seperate your rings, remove the scope and place a single piece of Scotch brand clear tape in both the upper and lower ring halves. Reinstall the scope and lightly tighten the rings and that sucker will never give you another moments trouble. Seems the attraction of the tape surface to the paint on the scope really holds tight and there is no reason to overtorque the ring screws.

Since doing that I have taken to putting the tape on all my scopes and the added benifit is no ring marks.

Hope this helps...............gary

 

[Temp9]

The most overlooked part of scope/ring fit is the base. If you haven't bedded your base yet, especially if you're on a 700, the base is most likely bowed due to the inconsistent height of the receiver sides. When the rings are mounted, they don't sit parallel to one another, but rather point along the curvature of the base. The end result is reduced ring contact leading to slipping and sometimes marring of the scope. Bottom line: bed your base.

 

[GONIF]

Make sure your base is not tweeked first , and if it is not this works every time .I know you guys are going to flame me on this , but If you use some automotive silicone gasket sealer on the inside of the rings it will stop that forever. Not something you should have to do if the rings were made to spec ,but a cheap fast permanent fix none the less.