Should you have to shim a leupold scope?

2muchgun,

I agree that something is out of alignment and we need more info and a picture would maybe help, too! I can't believe a certified gunsmith looked at it and reset the windage and could not find the problem. Seems the rings would be the first thing I'd check and certainly the tapping would be suspect. My theory is, if I can't put standard rings on a rifle and get it zeroed, I'm sending it back to the factory... plain and simple. None of my guns have shims or Burris offset rings but they are all lapped in and shoot better than I do! /ubbthreads/images/graemlins/smiliesmack.gif

Nikonut /ubbthreads/images/graemlins/grinning-smiley-003.gif
 
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Wrong answer....If his receiver is tapped out of line, it will cause the scope to do what is pictured in the drawing when you try to line it up, only instead of being over to the side in the middle, it would be jammed up in the corner at 10 0'clock or 2 o'clock. Because the scope cannot sit flat in both rings at the same time at that angle, it will rise up to one side. With alignment rods it would be visible to the naked eye. Burris Signature rings seem to be the cure all for people around here who have no clue what the real problem is. Yeah, they might work, how much stress will be transferred to the tube I don't know, but definitely some. A gunsmith would shim it and be done in 10 minutes........



In order for the receiver to be the culprit, it would have to be so far off that you could see it with the naked eye....that's why I said:

"unless it's so far off that you can see it by eye"

The OP said that the smith used alignment rods....if the receiver was drilled that far off, rods would never align.

What's a gunsmith gonna shim?
Crooked holes?
You seem to think the holes are crooked, regardless of the fact that the OP hasn't indicated anything of the sort.

Do you have a clue how the Sig rings work?
They work by shimming the scope without transferring stress to the tube since they move on all axi.

Like I said, I'm amazed by all the "information" in here. You've got the OP making trips to the gunsmith,(probably the same guy that doesn't know enough to check the mounts in the first place) shimming the scope, and spending all this money when there's a 99.5% chance that the mounts are bad, especially since they're Leupold mounts....well known for poor QC.

Since there's a loss of at least 50-60 MOA, use common sense and realize the mounts are most likely responsible. Sounds to me like theres a possibility of a mix-up in the rings(high ring in back, med ring in front, etc)

Bad mounts are very common while mis-drilled receivers are very uncommon these days.
 
I don't know what it is, but somethings not right. My guess is the rings are mis-matched. Leupold can send BT some shims but that's really not going to fix the problem. He's got the scope cranked all the way down (up) and he's still 3 inches low. I'm not experienced with shims so help me out. How much elevation travel is in a 1" scope at 100yrds? Can we say 12 inches as a hypothetical? So BT needs (3" + 6") 9 inches worth of shims under the rear base to have the reticle centered in the scope and be dead on at 100 yrds. Maybe .020" does buy that much, or is BT going to have a big old shim stack under the rear base?


2MG, I bought a .338 WM from a local gun shop back in the early 90's. I got the rifle, rings/bases and scope at the same time. Since I didn't have a boresighter and they did I just had the guy behind the counter mount it since they where all set up for it. I trusted the guy, he's a high volume PD shooter that goes through barrels like farmers go through toothpicks. Well needless to say when I went and TRIED to site the rifle in the scope had hardly any adjustment to it up/down or left. After alot of cussing and head scratching I noticed the scope didn't sit quite straight to the barrel. That led me to notice the rear base and the windage screws. One was cranked almost all the way in while the other couldn't of had but a couple threads holding it. I should have done a better job explaining it in my first post, but that's why I made the comment about the rear ring being centered on the base. Those things do happen.

edit, hickerx2 posted while I qas typing this. He's getting at what I was trying to say.

 
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Think what you want, I could fix that thing in less time than it takes me to type this. Since nearly all of your last post is wrong, I'm not even gonna bother anymore. Go get your signature rings, the ones I know nothing about, the ones that transfer no stresss to a tube no matter how phucked up the alignment is, and fix it for him. I'd be more than willing to bet that I've mounted more scopes than most, and seen more poorly tapped receivers than bad bases by far. That could be Burris new ad slogan, "Signature rings, bad-aids for the clueless......" Once again, a gunsmith would shim it and be done in 10 minutes.........
 
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Think what you want, I could fix that thing in less time than it takes me to type this. Since nearly all of your last post is wrong, I'm not even gonna bother anymore. Go get your signature rings, the ones I know nothing about, the ones that transfer no stresss to a tube no matter how phucked up the alignment is, and fix it for him. I'd be more than willing to bet that I've mounted more scopes than most, and seen more poorly tapped receivers than bad bases by far. That could be Burris new ad slogan, "Signature rings, bad-aids for the clueless......" Once again, a gunsmith would shim it and be done in 10 minutes.........



Yet again, you've failed to answer......shim what?
How do you shim holes drilled off-center?
How do you shim scope mounts horizontally?

Do you know how much machining error it takes to cause a loss of 60MOA in height adjustment?

Do you know how far out-of-center the receiver holes need to be to lose that much height adjustment?

I do....the holes would need to be drilled on the side of the receiver.

PLease tell us how to tell if the bases are too thick?, thin?....do you know the machining tolerances of bases?

You must since you say it's almost always the gun at fault and shimming will fix it in 10 minutes, even though you have no idea what the problem is.

I'm just wondering.
 
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Had the same problem once. The rear base needed to be turned 180 degrees. Problem fixed.



Yep, that's quite often enough to solve the problem. That would indicate that the base was off by a few thousandths(thicker at one end).

It's also a good point...I didn't think to mention it to the OP.
 
Hey everyone I had Leupold send me some shims and I did the work myself and just to settle all of the other arguments I used a caliper to measure the bases. Front base was .002" thicker than the rear. I place 2 shims under the rear mount and centered the elevation and windage adjustments on the scope. When I bore sited the scope, before I adjusted anything the scope was aiming two inches to the left and for inches high. Problem solved! Now i just need to start thinking of excuses because the way this thing is shooting, I know a miss isn't the gun's fault.

Thanks for the info
 
I had to shim my Leupold VX-II. I did the math as follows:
Distance from front to rear ring is 3 inches.
Desired rise in point of impact (at 100 yards) is 20 inches.
100 yards is 3600 inches (1200 times distance between scope rings)
20 inches/1200 inches is .0166
I added a piece of .015 shim stock (computes to 18 inches gain at 100 yards) and called it good.

That shows you that each .001 error across 3 inches will shift your point of impact almost 1 inch.

This formula will work with any mount if you substitute your mounts measurement for my 3 inches (I'm not sure how standard that is, this is an H-K QD mount that dovetails into the receiver cover) and your desired change in impact for my 20 inches.

While I'd prefer not to shim a scope, I was out of options and I'd rather have a shim and the adjusment close to center than have to crank the elevation to the extreme to be (barely) on target at 200 yards. I have seen no negative consequences in 20 years of using it like that. Go figure.

/ubbthreads/images/graemlins/wink.gif
 
When he mopunted the scope did he get the rings or bases reversed? The front ring should set a tad lower than the rear ring. Any scope may require shiming.
 
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