I just bought new Talley rings and bases for my 375 Mod 70. SOmeone had told me that the leuopold QD basesI was using have a reputation for working loose. Mine did so I am going to the Talleys as they are supposed to be very stable. I am attempting to mount two scopes in Qd rings so if ever I have a scope issue I can just pop one off and another on. One is a Leica 1.75x6 and the other is a 3x12 S&B. My problem is that with both scopes I am out of clicks and it still is an inch to an inch and a half low at 25 yards. Any ideas about how to correct this? Thanks

Wow... shouldnt thoughs talleys be dead on bore sighted at zeroed when you mount the scope?

Just currios about the talleys,I dont have any talleys on M70s , just luepold mounts and all my 4 winchester m70 rifles were pretty much right on bore sighting when I mount the scope at zero adjustment.

99 times out of a hundred the problem that you are having here is because of too much variance in you Winchester reciever. You can shim the reciever, mill the receiver, mill the front base down or sometimes Talley will have bases of different heights to correct the problem with Winchester recievers. Put a good straightedge on the receiver and you'll see what I mean. What you are seeing isn't uncommon. I've got a model 700 that has the holes drilled so far off center you can see it without a straightedge. Bad tolerances aren't limited to Winchester.......DJ

Yeah, what DJ said!

Scopes are designed, and work best, when their adjustments are in the mid range. You woul dbe surprised how many "problem" rifles ro scopes are cranked all the way to one extreme. THis is begging for trouble.

YOu have manufacturing tolersances working against you here. All recievers, rings, bases, and scopes have tolerances that may or may not work in your favor. Looks like the stack was against you here.

If you want to keep the Talleys, you can shim a base, recut a base, or modify the action bridge. I reccomend shaving the front base until you can get the scope zeroed with it in the middle of its adjustemnt range. ANd I would work on the windage too, while you are at it. THe elevation work is best done on a mill, and minor windage work can be done with a file

For those who have the machinery, build the bases mounted on the receiver. You can machine the hiegths of both the front and rear scope base at the same time as well as cutting the dovetails for the Talley Rings. You can measure the hole patterns of the front and rear ring and bridge and drill the bases so the holes match.

This way it doesn't matter what the factory has done, the scope will line up.

The barrel can also be pointing in a different direction to the receiver.

I have a 223 WSSM of a mate of mines here where I have done the trigger and bedded his rifle. This rifle has the barrel point down.

Life is a bit harder with Talley vertical split rings but you can check if it is the receiver by loosening of one of the mounts. For example, if you are using all the elevation in the scope you will usually find if loosen the rear ring the scope will move up. Thus when you tighten the ring down you push the scope down so it and the barrel are point in different directions.

This problem can fixed by shims under the base. If you put shims on the rings and you 20 thou or so you will probably crush your scope.

If the problem is the barrel is crooked in the receiver then apart from trying to get that problem fixed the easiest way is to bed the scope in the rings at an angle. That is what I have done with this 223 WSSM.

I centred the scope and then cut some very small shims from a soft drink can and put them in the rear in and just drop the scope in, but not put on and tighten top rings. The scope just sits there and you bore sight. Add more shim until it is roughly right. You then leave the shim there and put bedding compound on both front and rear rings. The scope will now be bedded at an angle that rought makes it the same as the barrel.

I use Devcon Titanium and after it has cured, pull the scope out and remove the based and bottom ring and throw them in boiling water for half hour or so. That fully cures the Devcon titanium which sets about as hard as a poor grade of aluminium, say like an aluminium saucepan.

As a side note, this gem of a rifle would not feed the second cartridge. Fortunately that was easy to fix by bending the magazine spring to put more tension on the front of the follower.

It is such a great shame that the Model 70 has so good a design, especially the bedding configuration but the execution of that design is as bad as the design is good.

Mike

Maybe but it is interesting that the Leuopold mounts worked fine with both scopes. They just worked loose.

Is it possible that you have the bases switched?
The front base is about 1/16" thinner than the rear.

WHen you say the Leupolds worked loose, what exactly happened? ANy tiem I use lever rings, I lightly tap them with a rubber mallet. If you can flip the rings easily with your fingers, then they are too loose. Most people don't have their lver rings tight enough.

As stated earlier, all maufactured components have manufacturing tolerances. IT looks they were all astacked against you here. THe Talley rings and bases have tolerances that could have gone your way, but did not. The Leupolds happened to work in your favor.

Was the scope pretty much centered in its adjustment range with the Leupold rings and bases? I am guess that you were about out of adjustment with that ring and base combo.

Before I did anything, I call Talley. I think they have seen this problem and can help you.

I'd switch the bases with each other first to confirm what MichiganScott said. You can't be sure until you try, but there are different bases that will fit the screw patterns, and in some sets the front and rear are in fact different heights.

I had this problem with a set of Talley's on a Whitworth Mauser and Talley custom made me a new front base at no charge that allowed me to zero properly. Good service. Bob

The trouble is the rifles receiver is out of square with the world around it...you can surface grind the receiver or you can have custom bases made..or you can have Griffen and Howe install a QD side mount...just some options.

I would have the receiver surface ground myself and then have custom bases fitted to it, that way it will return to zero more precisely..I discovered this many years ago with QDs, if the receiver is off and any kind of a bind exists then they don't return to zero with the accuracy I wanted....