I have recently had a spate of bad luck with scopes rings and bases. Leupold mounts that moved as soon as the temperature went below freezing. A Nikon scope that slipped in the mounts when the temperature went below freezing. Objective lens covers on a pair of Nikon EDG 10x42 mm binoculars that went on tight in the comfort of my home only to fall off due to gravity in mild, but below freezing temperatures.

I replaced the scope and rings with a Bushnell Elite 2.5-10 x 40 mm and put Burris extension rings complete with that handy Burris paper on the bottom of both rings. This was on an old Remington 760 pump in 30:06. I suspect that the rings were not snug in the base as the old 760 was minute of acre until I put on the new rings. It shoots well now. A salesman I know and trust always said the Nikon scope tubes were soft. I know they were not bead blasted ( surface hardens the aluminium tube whether a scope tube or a phonograph tone arm), but soft I cannot say. The Bushnell tubes are hammer forged so they should be a fairly skookum tube. The scope that gave me the grief was an old Nikon Monarch in 1.5-6 42 mm objective. I have a lot of different rifles and scopes, but this was new to me.

The screws were tight. I have buggered up scopes from over tightening, so I am very careful about screw tension. The bases I believe were just a trifle too narrow. Between the lens covers falling off and the scope slipping on an '06, I wonder just how much reduction in tube diameter occurs when the metal cools?

Anyone else have experience or thought on this? Please chime in.

Interesting.

Would you please specify which Leupold and Burris mount systems you refer to? Were the Leupold rings lapped?

The "mild, but below freezing" was about how cold?

I would think it was poor fitting bases and/or rings and possibly coupled with incorrect tightening despite the efforts. Was this a proven setup in warmer temps?

The coefficient of thermal expansion of aluminium is roughly twice that of steel, so if you have an aluminium scope tube and steel rings the tube will contract more than the rings as temperature drops. The effect on dimension will be very small though, about .00006 inches per inch per degree F.

One more decimal point

.000006 per deg per inch steel

Ive hunted below zero with no issues not to mention air travel and -60f in the cargo hold of a plane

Yeah you're right Ted, I miscounted the zeroes. 6x10E-6. Bugger all, in other words.

The rings were 30 mm, dual extension Leupold rings. They were not lapped. The ring portion were apparently over sized, and the rear base was apparently undersized. The temperature was about -5 centigrade. Cool, but mild.

The rings that came to the rescue were Burris, one inch, dual extension rings. I used the paper adhesive that came with the rings, figuring it cannot hurt. The rifle now is very accurate.

If you have a rifle that is giving you fits, changing the rings might be worth a try. Up until this, I thought they were fool proof.

Okay, you used extension rings, but which mount systems? Each manufacturer produces more than one. Were they Dual Dovetail? STD with the hokey rear windage screws? Or something else?


Did you mount these or acquire the rifle with them already installed?

30mm failed

1" is ok

Dude! You gotta be kidding

You have a mess

� a serious case of over-think here�.never seen anything of the sort with plain-jane Weaver, Ruger, Leupold, or any other rings even at -25� C or less. Stuff would be going wonky every time a jet-liner went up if there was a real issue here.

A place I worked used cold to their advantage, but real real cold. Uber-cold infact. A large cylindrical metal piece was bathed in liquid nitrogen overnight, <-300 F, taken out and dropped in place. Once it warmed and expanded it was a snug fit, locked in for eternity. Part of the business end of a rock crusher.

I think wonky mounts has more to do with STD mounts, mismatched parts, loose, and/or wornout parts or some combination of the above....

The mounts were conventional mounts. I doubt a dual dove tail mount exists for a Remington 760. The rear, windage adjustable mount was a few thousandths too small. The bit about the eye cups falling off the Nikon EDG binoculars really drove home the point that this aluminium really shrinks when it gets cold. I have had these binoculars for a few years, and optically they are fine. The objective lens covers would always come off in my back pack. Now I know why. A wrap of electrical tape will end this.

As to equipment subjected to severe cold, like that of an aircraft flying at 30 000 feet. The equipment is not being subjected to shock like recoil. It is contained in very well padded cases and is well secured. My scope only moved during recoil with full power 180 and 220 grain loads.

I think the aircraft itself would be wonky...

Conventional mounts?

If referring to "Redfield-style" windage adjustable Leupold STD mount, they are known and confirmed junk. Parts wear out, and although supposedly interchangeable, multiple manufacturers produce them, one of which is Burris. Leupold and Burris also make other styles too, beside these and dual dovetails, just saying Leupold or Burris means nothing and desiring forum readers to sort through the endless possibilities you MAY be referring to is wishful. Narrowed it down a bit with extension - but then we're right back a'guessing. If you desire to be clear - then by all means provide less doubt.

Not going to try solve the rings/base issue but want to make two comments. Use either all steel or all aluminum mounts and rings. The two don't seem to work as well together for some reason.

Second, try a dab of 3M Scotchkote (sp?) it is almost like a rubber cement. Just a dab in the rings will solve a lot of slippage issues. I comes off with various solvent type products and leaves no ring marks unless over tightened.

If the scope was mounted and the rings were torqued correctly the wouldn't have moved.....this I have no doubt

The shrink factor wont come into play under torque

The rear base of the Redfield style, dual extension rings was too small. Undersized, might be the correct term. When I got home I took the rings and scope off. They were tight. Very tight. This is not my first go around with poorly fitting rings (or bases).

I had fired this set up in warm weather and experienced none of this. The lack of engagement between the windage adjustment screws and the rear base was not visible. The gun was not accurate no matter how hard I tried. A simple scope and ring change out, and I have a good shooting rifle.