Scopes & Rings....

[Powerstroke]

Question regarding a scope moving in the scope rings.

I have a buddy that just purchased a .300wsm laminated Tikka. The scope he has on it is a Nikon and this was the first time he's had it out shooting today.
The gun looked very promissing with the first three shots basically through the same hole @ 50yds...... we moved the target out to 100 and the groups actually started opening up a little. You can see where the scope is moving in the rings. Sugestions on how to keep this from happening ? They are the factory rings supplied with the gun from Tikka.

 

[DrMike]

Powerstroke,

First thing is to ensure that the rings are tight and that there is no grease on the inside of the rings. The screws may need Loctite to secure them tightly. Was there grease or oil on the rings proper so that the scope is essentially lubricated, thus allowing it to slide during recoil?

 

[JDMAG]

some very thin double sided sticky tape may help. I used to use some stuff that seamstresses used, cut it to fit the rings, and it provides a slight amount of grip.
This stuff was as thin as Teflon plumbing tape. Come to think of it, that might work also. I never had a scope slip with this, come to think of it , I didn't have them slip before I started using it either.
So why did I start using it?

 

[JD338]

Powerstroke,

You may recall I had the same problem with my nephews 700 XCR 338 RUM and a Nikon scope. I really torqued down the ring screws and it solved the problem.

JD338

 

[Powerstroke]

Thanks Guys.....

I'm fairly confident the rings and scope were clean prior to mounting. ( just speculation though )

He may need to try the tape trick... I wasn't sure if there is / was a specific type / prefered type.

We had actually loosed the scope up after we noticed it moving and re-adjusted slightly. I didn't tighten the screws back down, but I do know watching it there are T. I. T. E. beyond spec and it still moved.

 

[DrMike]

The Tikka Optilok design is a good design that should not slip. You didn't per chance get 30 mm rings for a 1 inch scope, did you?

 

[Powerstroke]

I've never used / owned one myself, but I've always heard good things about them.

No, not 30 mm rings.. that would be a difference of 4.6mm between the two.... kind of like ringing the dinner bell / triangle.

 

[DrMike]

It certainly sounds as if there is perhaps a thin layer of oil on the rings, or they simply haven't been tightened sufficiently. You should have approximately the same clearance on each side of the ring when they are properly tightened, not quite closing the gap.

 

[Powerstroke]

We didn't have the scope completely out of the rings when we loosened it up..... I "think" but not sure that one of the sporting goods stores mounted it and bore-sighted it.
I always use a non CFC brake cleaner myself to clean oil residue off as it will dry clean and not leave a residue. It's got to come back off so he may need to get his hands on some of that.

I did look at it, and the gap is even from side to side.. not excessively torqued more on one side than the other. However... the gap is probably greater on both sides than what I'm used to seeing with the Leupy rings..??

 

[DrMike]

It is always a good idea to clean the rings with the brake cleaner. While the 300 WSM is not a hard kicking calibre, there is nevertheless recoil, and any looseness or any lubricant will permit slippage.

 

[Desert Fox]

Try lapping the ring. I always lap my rings and I can't remember having slippage issue. Also another trick I learned is to bed the ring using epoxy.

 

[cloverleaf]

Tighten the rings to specs for the scope or ring manufacturer. IMHO I would be leery of shimming the rings as I have heard that it puts stress on the scope. Equal gap between the rings is good advice but if that dont do it I would think about lapping them. You could try another set of rings. Like anything else I assume the tolerances can vary. Just my .02- CL

 

[Greg Nolan]

Powerstroke
Desert Fox nailed it!!!!!!
I thought I knew about scope mounting untill I discovered that rings are not truly aligned from the factory for your rifle. How can they be? I discovered that lapping your rings does more than anything else you can do and it's doing it right. Midwayusa has the Wheeler Engineering scope ring alignment and lapping kit. 1". 227261
I used to fight the sliding scopes on my Ultra magnums and crank the rings down so tight it warped the scope tube. After a few times lapping the rings I was sold. The rings said it all. You can see where the lapping was taking off metal and now the rings gripped like they should. They were only touching the scope about 5% of the surface. Now they touch 60 to 80% and with normal 25"pounds or torque nothing moves.
Yes it's $37 but it will save hundreds of $s in ruined scopes.
I know I sound like a commercial but I have ruined a couple of expensive scopes in the learning process.
If you have any questions send a PM to me.
Good Luck
Greg

 

[Desert Fox]

How's this for an eye opener. It's a MK4 ring mind you. After I lapped the heck out of it, You can see the improvement, but still not a 100%. Can you imagine not lapping it at all. I paid top dollar for these set of ring. You think I don't need to do anything to it.

 

[DrMike]

This is a great visual demonstration DF. Thanks. Good stuff.

 

[Powerstroke]

Excellent info guys... I appreciate the input

 

[Powerstroke]

Just an FYI..... Midway Has the Wheeler Scope alignment / lapping kit on sale right now..... I did go ahead and purchase one.