I have a mauser action barreled in .270 with Leupold base and rings. The scope has been adjusted down as far as is allowed with the adjustment "screw" but is still hitting 2" high at 50 yards. It seems to me a shim is in order. On the front of the base? What is the procedure and who has them?

I use soda pop cans for material,easy to work with non-rusting and run about .005 per thickness.Each .001 will give you 1" at 100yds. with average scope tube lengths

Oddball, what height is it hitting at at 100 yards. If you use point blank range and want to utilize the flat trajectory of a .270 you should be around 3" high at 100 anyway. I do agree that I dont like the adjustments at the bottom of the range. No real basis for it though, I just like some leeway.

BTW, Brownells has shims for most scope bases.

Chic Worthing

[This message has been edited by Customstox (edited 01-05-2002).]

I use a piece of plactic from an old milk carton. It tends to grip the scope without marring the finish, does not rust, and molds a little to the scope for a good grip.

My .270 hits about three inches high at 100yds, and comes back to zero at around 240yds or so. Try your rifle out at longer ranges to see if it hits where you want it to. You may not have to shim at all.

ZM

Oddball: I too had a problem with Leupold bases on a sporterized M98. Although the rear bridge had been ground, the rear base was several thousandths(about .030 if I remember correctly) higher than the front base. I determined this by laying a straight edge across the bases as installed on the receiver. I also measured the difference in the height of the front and rear bases, and it was about .375" difference. I talked to a rep at Leupold and this was not to spec, the rear base was higher (thicker) than the dimension he quoted. This would definitely cause the rifle to shoot high, but I never got to that point as I knew something was amiss. They sent me a new set of bases, and that cleared up the problem. Perhaps yours are from the same batch. I bought mine from Cabelas. As usual the people at Leupold did what was necessary to rectify the situation.

FWIW, by far the easiest way to shim is the Burris Signature rings with the off-set ring inserts. The off-set inserts act like a shim, but you don't have to monkey with soda cans, and it looks better. HTH, Dutch.

you won't be able to shim it that much. A loupold scope has about 30 MOA in each direction so to put you centered in the scopes adjustment you would need to remove 30 MOA of metal from the front base or ad to the rear now if your rings are four inches apart this would be about .034" and would bind your scope to the point that it would be about as good as a $30.00 Tasco. sounds to me that you got ahold of one of the bases Wild cat is talking about.
either way you need a new set of bases.
Kerry

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If you can't hunt, fish. If you can't fish, Hunt

Depending on the bases you have, it's not too difficult to grind off the bottom of the rear base with a Dremel tool and a stone.

When your scope is adjusted as far down as you have it, two things happen. First, you aren't in the center of the focal plane and therefore your optical quality is at less than optimum. The bigger problem is that adjusted to the end, the manufacturers have told me the scope is much more vulnerable to internal damage and more easily knocked off zero.

[This message has been edited by Bob338 (edited 01-07-2002).]

Don't listen to all of the B.S. that's flying through the air around here. Use the filter that God gave you to figure out what makes sense.

Soda can material would work, but I would suggest just plain strips of aluminum foil placed under the scope's front ring. Several thicknesses will be required. It is invisible once installed.

One more thing: Before you start shimming, check the rear ring to see if it is seating in its base properly. If it is being held high for some reason, you would find the same result as a low front.

My third-of-a-century old Sako had this problem with Redfield mounts. I solved it with aluminum shims as stated above and the original 3-9 Leupold on it is amazingly unharmed. (The misalignment of many scope rings is far more than that caused by shimming. Don't worry about "bending" or creasing your scope.)

[This message has been edited by Stonecreek (edited 01-06-2002).]

Oddball;
As Dutch said, Burris makes rings with inserts that takes care of the shimming.
Sako/Tikka also make similar mounts.

Vasa

Oddball, there is some good information here for you so don't pay too much attenion to Stonecreeks BS statement. Even his method will work. Bob338's idea of grinding the front mount will make it worse.

I have not seen the offset rings that Dutch mentioned but if everything else turns out to be as spec, those might be just the ticket. It will also have a nice cushioning effect of the rings happen to be off line and have a tendency to bind the barrel.

I personally don't like shims and would rather modify the bases to get them in the range, but it involves a lot of elbow grease or a Milling machine.

Good luck and tell us how it worked out.

Before you shim it make sure the rings are on the same plane horizontal and vertical.
so that when you do shim it you are making the scope rings level not angled to each other.

Stonecreek you can Tweek the S**t out of your scope but if he has a .030" misalignment then I would like to see it survive and stay on zero for anything longer then one hunting trip.

Kerry

Can't I just put a thin peice of materiel between the front ring and the scope base? Since it's a one piece base the scope shouldn't bind at all.

Oddball: Here's what I would suggest, as this is one of the steps that I went through in my search for answers. Try to establish if the top surface of your base is parallel to the bore. Try to find a small machine shop. (hopefully run by a rifle crank ) Remove the action from the stock, and the trigger from the action first, but leave the base installed. Have them set the flat bottom portion of the receiver on blocks on a perfectly flat surface, and check with a dial indicator to see if the top of the base is parallel to the surface .005 to .010 higher at the rear is okay, even desirable but it should (theoretically) be parallel. Any deviation from from these specs. means the base or rear bridge must be ground, or shims must be used. If it is within specs. there is a problem with the scope or the barrel is bent or not square with the receiver. I would suspect it to be a problem with the rear bridge or base dimensions. If the base is not parallel, loosen the screws on the low side and shim so that the rear of the base is .005 to .010 higher than the front. Or ask what it would cost to have the base ground the proper amount (sit down for this ) This should have you boresighted vertically @ about 25yds. Do this while your still at the machine shop so you can check things out with the dial indicator. A word of caution: sometimes there are small "steps" of a few thous. on the bottom of the receivers. Don't let this throw you off. This should give you some answers From what you describe, I would suspect that you will need about .030 shim, this is too much and will cause a bind unless you shim the base, not the rings. I doubt that you would be charged much (if any) for the service I described as it would only take a few minutes, and then you will know exactly what is going on. I was not charged anything when I had this done.

[This message has been edited by wildcat junkie (edited 01-06-2002).]

[This message has been edited by wildcat junkie (edited 01-06-2002).]

[This message has been edited by wildcat junkie (edited 01-06-2002).]

This is getting much more complicated than it needs to be. Put two thicknesses of aluminum can stock between the front base and the receiver ring. Remount the scope. Your done!

quote:

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Originally posted by Oddball:
I have a mauser action barreled in .270 with Leupold base and rings. The scope has been adjusted down as far as is allowed with the adjustment "screw" but is still hitting 2" high at 50 yards. It seems to me a shim is in order. On the front of the base? What is the procedure and who has them?

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[This message has been edited by scot (edited 01-08-2002).]

I have a different take on this problem:

You may have sprung the action.

Check the rear screw to see if it is torqued down too tight. Loosen it all the way then begin to tighten it and see if the rear bridge moves. Even with the screw sleeve as protection, you can still overtighten- the screw sleeves don't make perfect pillars... You could damage the scope if this is severe. A re-bed might be necessary.

You may have sprung the action.

..."I have a mauser"

Could be that the bridge was not reshaped properly. If so ,I would use a one piece base. Shim as necessary and epoxy the whole works solid. It may seem a bit of a fly by night solution , but is will works well.