Help with scope sighting???

[erict]

Alright guys, I've sighted in several scopes and don't need basic advice on sighting one in.

I do however; have a scope that is mounted, clicked all the way over, and still is 2 feet off to the right at 100 yards so something is not lined up on this rifle. I'm trying to find the source of the problem and I'm sure the rings are at fault.

The Rifle is a CZ 527 varmint in .223 and the Scope is a Simmons Aetec 2.8x10x44, both seem to be great quality items. The rings are of unknown origin but seem to be well built and of good quality

I've never had to shim a scope and wonder if it's worth doing or should I just search for a new set of rings? I have even thought of filing the rings on each corner to square it up. I don't know if they are at fault and I also don't want to ruin the finish on any of this stuff since it is in great shape.

Any suggestions? Thanks, Eric

 

[308win]

Are you sure you have the correct bases and rings? Are you certain the scope is working properly? (I have had only one experience with a Simmons and it wasn't positive.) Is the action/barrel assembly fitted in the stock correctly? Are the base mounting holes centered on the bore axis? If not and you bought the rifle new the factory should replace it.

 

[erict]

Well heck! I'm sure of most of it but I suppose I'll have to remove it all from the rifle and try it on another. I hate to have to re-zero any of my other rifles to do so though.

The rings,bases, and scope all fit tight and snug and all screws drop nice and flush in the mounts. The bad thing is, what might be off one little millimeter on the rifle itself is going to magnify greatly at 100 yards. So I can't see anything wrong just glancing at it.

 

[ADKWOODSMAN]

Shimming

If your rifle groups to the right, shim the right side. I've used tin foil in layers and it has been good to me. Also try the box drill to see if the scope is any good. Ten clicks up shoot 1 shot 10 clicks left, shoot one shot, ten clicks down, shoot one shot, ten clicks right then fire another. Repeat and see if the shots are close to the first. I'de suggest 100 yds.

Hope this helps.

 

[308win]

I am a long way from being an expert but if you are shimming the scope in the rings it seems to me that you really are masking the problem. I could see shimming the bases for elevation but not windage (not sure how one would shim bases for windage anywho).

 

[krimmie]

Some times this can be a problem if the rings aren't screwed into the base evenly. Try unscrewing the rings a bit, then re-screw evenly.

 

[benEzra]

Are the front and rear rings identical on this rifle? If so, what effect does swapping them have?

 

[erict]

I wouldn't think it would have any, but if one of them is not true it may help a little bit. I'm going to tear it down tonight and see if there are any burrs on the castings of the rings and look for anything else strange looking.

I'll let you guys know how it goes and we'll see if we can figure it out, thanks.

 

[RonSC]

Assumeing you are using the correct rings (CZ 527 factory rings cannot be switched front to rear or visa versa) I would suggest removing the scope and "mechanically centering the reticle usining widage turret. This is accomplished by turning the windage adjustment (right or left) untill it bottoms out. Then simply reverse this proceedure in the opposite direction and COUNT (audible) clicks or observe the total number of increments (hash marks) it takes to bottom out in that direction. Divide the result by (2) and this is the number of clicks required to "mechanically center" your scope. Again re-adjust resultant number of clicks in the oppositr direction and you are done. Your reticle is now in the center or mid-point of its adjustment range. This may or may not help your particular problem but it is always advisable to do this with any scope prior to mounting in order to take advantage of it's optimum adjustment range. While the scope is removed I'd re-check the rings per previous posts for both correctness and proper fit.

Good luck,
Ron

 

[Vern Humphrey]

RonSC has given good advice. I'd get another scope, and do the same, then mount that scope and see if it's nearly centered when you bore sight. If it is, you have a scope problem. If not, you have a rings or base problem.

If it's a rings or base problem you can shim, or you can replace the rings and/or bases. But before I did that, I would contact the maker and discuss the problem with them.

 

[erict]

The bases look dead on but the rings have very slight differences between front/rear and one of the caps seemed to fit better when turned around as opposed to the way it was. I'll try again tomorrow and see how close she'll get.

I just centered it before I read this. I wanted to do that so I could have as much play as possible.

 

[erict]

Here's a pic of the rifle and here's a pic of the bases. I can't get a good close up pic but you can see that the rear ring looks slightly tilted to the left.

 

[erict]

Ok got her running right. The top cap on the rear ring seemed to be misaligned one way and fit tight as a glove the other.

I guess when they put the ring cap on they assumed it was a symetrical part (I would have also) when in fact it is not. It must have binded the scope up just a bit enough to get it way out of line at a greater distance.

Here's a pic when I went out and sighted it in. You can see where it was a foot or so off still from me just sighting it down the bore. I got it closer and put 2 in the center, then moved it to the next target to make sure it was on.

thanks again for the advice and encouragement.