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But when you use a screw driver you can feel the screw is looser. The base moves but is still tight.

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There lies IMO one of the big problems regarding tightening scope mounts, the "screwdriver".

When a screwdriver is selected which has a blade broad enough to engage both sides of the slot on the rings, you could end up with a screwdriver powerfull enough that it is possible to badly over-torque the mount clamp system, and something is highly likely to give.
In this case it's the tip of the clamping claw.
Once that tip is deformed, the claw is not able to draw the scope mount down tight onto the receiver, and the result will be just as you describe, where the screw is still tight but the scope base is able to move.

(Edited to add.........
Of course it is still possible that the metal was too soft to start with and would have deformed anyway).

I used a screwdriver once for tightening the clamp nut on a set of scope rings.
That was back in 1979 and I haven't used a screwdriver for that purpose again.
IMO it's better to use a coin of the correct size.

Our Oz 10 cent piece is just a tad smaller in dia than 1 inch and it's thickness fits the slot nicely.
It does the job well, and will get the nut plenty tight enough.
You would really have to excell yourself though to over tighten Ruger rings with a coin.
With a screwdriver however, it is not at all difficult to over-torque those mounts.

Edited by 4seventy (02/12/08 06:49 PM)

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I'm sure the screw driver is part of the problem, but the real problem is the soft steel of the nut.

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Totally possible that ad heat treatment is the problem, but my experience follows:

The mounting technique that might solve the problem {?} I use and have used for many years, and the one we used mounting and boresighting scopes in the gunshop/store is this:

The scope ring is placed on the receiver and grasped firmly. As the nut is being tightened, the ring is jiggled with the other hand in order to help the ring find its own center and seat itself. You can actually feel this occur.

It is easy to tighten a Ruger ring when the ring base is NOT securely seated. This last bit is what I believe causes the lion's share of the problems people say they have with the rings. "Jiggling" the ring and making double sure it is seated prevents the misalignment.

I believe 4seventy is right; misalignment normally causes the problem. The screw is made to be softer than the receiver, and should be. No doubt some may be too soft, but if the ring is merely slapped on the receiver and tightened, without being set into its base, it is very easy to get a "bite" on the screw {clamp} where the screw feels tight but the clamp is only grabbing on the clamp edge. This misalignment I have seen and experienced during the scope mounting process and rectified while mounting. Every time it has occured to me, loosening and jiggling the ring as it is being tightened has solved the problem. As mentioned, I have only had long-term shooting experience with several Rugers, but mounted many in the shop, some on heavy kickers and none that came back goosed-up.

I am guessing that a ring clamp that is really too soft might be a worse offender in the misalignment process because it might feel like it is biting securely when it is not and then naturally later under the stresses of recoil it lets go. Those I've heard of resulted in scattered groups. I'm still having a problem seeing how the POI shift could occur and maintain group size. I have heard of this problem, but never heard of group size remaining tight. I never had one return to the shop where I worked, having only heard of the problem on the internet.

As for misalignment, DoubleD, your first pic looks like it shows a scuff on the ring base on one side. I can't say I remember seeing this before but that might indicate improper seating of the ring and cattywampus pressure under recoil?

Good thread and thanks for posting the pics, too. All this might save somebody else trouble.

As far as you rings are concerned, if it was me, I'd file the burr off, remount using the jiggling technique and I bet the thing won't let go again.

No promises!!

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