I filed off the receiver hump and still running out of scope adjustment... Next?

542 Views 8 Replies 6 Participants Last post by ccw1911, Apr 27, 2003

1884

Discussion Starter · Apr 26, 2003

I filed off the receiver hump and am still running out of scope adjustment. Taking off the hump helped but… at 25 yards the with the scope elevation knob all the way up and using high-velocity ammo the crosshairs are dead on. So at more that 25 yards or with sub-sonic ammo I am low.

I do not want to go to the expense of new ring right now.

I guess I will try a barrel pressure pad under the barrel next. Suggestions on materials and thickness welcomed?

I know shimming under the scope base would be a bad idea but has anyone shimmed under the rear ring base with good results?

I have never had a 10/22 be this much aggravation before.

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4769

· #2 · Apr 26, 2003

Shims

For what its worth I shimmed the rear scope base on my set-up with two thicknesses of an aluminum beverage can cut carefully to size. Used blue Locktite as well. It's been on there solid as a rock for two years now. Never a problem. Sorry to disgust some of the purists out there, but I've always been a function-over-form kind of guy. (Also cheap as Hell!)

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bigdaddytacp

· #3 · Apr 26, 2003

Try swapping the front ring to the rear and then try a brass or alum can shim as the other post suggest.....sometimes the rings are just a little different in height and the swap helps........good luck and good shooting!!

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Chief Dave

· #4 · Apr 26, 2003

If you decide to shim, I'd think it would be, by far, better to shim under the base, rather than under the rings.

If you want to try it on the cheap (But end up with a PERFECT fit) get a piece of one inch barstock and lap the rings, concentrating on the front ring at first, then both of them to match them. You should be able to lap it right to where you want it with the bar and some coarse valve grinding compound in just a few minutes time..

Fact is, ALL new base/ring setups should be lapped before a scope is ever put in the saddles.

Ron

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ccw1911

· #5 · Apr 26, 2003

Double check that you have all the hump out, a little will do a lot of damage. I wouldn't try to shim the barrel. Do your rings have cloth inserts? If so they can cause grief. If you shim the scope do it between the scope and rings not between the ring and base.

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Chief Dave

· #6 · Apr 26, 2003

IF you shim between the base and the receiver, the ring alignment will be as straight as the scope base is straight, however, if you shim between the base and the rings or between the rings and the scope, you have maybe got it to shoot where you want it, but the scope will be in a bind from being set on the shims on one end.

A precision piece of optics should NEVER be intentionally put in a bind with shims.

Ron

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698

· #7 · Apr 26, 2003

Rather than go the duct tape & bailing wire....

route, just get a Millett 10/22 base, a pair of Burris Signature Zee Rings, a set of Burris eccentric inserts, and do it right the first time without all that shimming and lapping crap. However, if you like to do it the hard way, good luck!

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1884

Discussion Starter · #8 · Apr 26, 2003

route, just get a Millett 10/22 base, a pair of Burris Signature Zee Rings, a set of Burris eccentric inserts, and do it right the first time without all that shimming and lapping crap. However, if you like to do it the hard way, good luck!

Sorry but you ain't listening "I do not want to go to the expense of new ring right now." …

If you are going to cough up the $60-70 dollars needed I will be more than happy to do it your way.

OK looks like lapping and shimming under the base next.

Thanks for the advice.

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ccw1911

· #9 · Apr 27, 2003

Shiming is a last resort when you can't afford to do it right. Since this is what was indicated I wouldn't think he has a expensive scope on it. Unless you go to extremes your not going to put the scope in a bind, the top ring will conform. Use soft shim material. If you tighten down enough to crush the scope it don't matter what method you use. I don't like shiming between the base and receiver because then you lose a lot of the contact area. More stress on the screws and the real probability that the base will come loose.

For the record I myself wouldn't shim unless it was an emergency and then only on a cheap gun and scope.

None of these options are the first choice just a way of getting by till you can do better. Find the problem and fix it, this other stuff is a band aid. I'll go thru my check list in no certain order.

1. Recheck the hump. it's easy not to get it all out.

2. Check the mount, make sure it is the same thickness at one end as the other.

3. Check the rings but switching them to see if that changes anything.

4. Check the rings to see if they are square down on the mount when tightened. I'm assuming you have Weaver type. Some of the cheapies don't sit flat on the mount when tightened.

5. Check the scope by mounting it on another rifle.

6 If you can put the whole mess on another rifle you would know the rifle is at fault.

7 Check the wedge screws that hold the barrel tight.

8 Use a magnifing glass and check the muzzle for damage, it doesn't take much to deflect a bullet and it can be amazingly consistant.

9 Check the alignment of the bore and the top of the receiver. Hold the rifle in a rest or vise without the mount and level the top of the receiver where the mount fits. Then insert a cleaning rod in the barrel with enough hanging out to set your level on. The two readings should be close, if not there's your problem. If they're close bolt your base down and check the top of it compared to the bore. If your still good put the rings on and check those against the barrel.

This should give you some things to check out that won't cost you a dime and should uncover the real problem.

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