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Misaligned Scope mounting holes

 
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  #1  
Old 07-25-2014, 02:03 AM
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Join Date: May 2014
Location: Tucson (Vail), AZ
Posts: 172
Misaligned Scope mounting holes

Howdy all,
I recently traded a nice .308 Navy CMP M-1 Rifle I'd had for years for 2 shotguns, a .38 Special Bullpup for my Granddaughter at College, and a Remington 700 .308 VTR plus $200 Cash. Dan, the guy that I traded all of this for had bought the VTR new with a factory (?) Scope, but had in the last several years had never got it adjusted onto paper. The VTR was essentially new with about 2-3 boxes of shells through it. Dan wanted that M-1 bad and hadn't had any luck with the VTR.

Being smarter than the average Bear, so I thought, I figured that I would throw a set of of Burris mounts and Rings on the VTR and use the Pos-Align rings to bring it back into alignment and have a good Feral Hog hunting Rifle. Not to be!

I set it up, zeroed the scope, took it to the 25 yard range for a 100 yard zero and it was hitting 24 - 26" low left at 25 yards when I maxed out the windage. Thought I had the rings in backward, rechecked the install, no luck.

Changed the pos-align rings to .10 re-zeroed the scope and got to about 14" off the target. Played with various combinations of rings trying to get it even close to the paper. Ordered some .20 rings, but decided I had a bigger problem. Took the whole thing back apart down to the receiver, put a mounting screw in the back Scope mount screw hole and made a loop in the end of some 4 Lb mono fishing line, looped it over the screw and stretched it through the center of the other mounting screw holes and found that the holes were misaligned by about 2 mm to the right, at the bore. (about 26" total length from the back hole) The line intersected slightly the side of the barrel. (Triangular) rather than lined up down the center.

Like some others, I want my stuff right, so the question is: Can a gunsmith screw in some screws, or otherwise fill the holes, grind them off flush, re-parkerize and re-drill and tap new mounting holes in the receiver safely? I've cleaned up and rebuilt a lot of rifles and shotguns, but never run into this, to this extent before, but am sure someone out there has. For some reason, I prefer my scope to be adjusted as close to zero in both directions and I've got a felling I know what I'm going to have to spend that $200.00 on....LOL

Been advised to get rid of it, but am stubborn and won't pass on a problem to some poor unsuspecting LR shooter. Will either fix it or scrap it out for parts.

Any advice is appreciated

Bruce

"The words "Dedication" and "Commitment" are frequently used in the wrong context in conversations and statements The difference is simple: You may be "dedicated" to having a Barbeque, but the Pig is "committed"".
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  #2  
Old 07-25-2014, 07:53 AM
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Join Date: Jul 2004
Location: Texas
Posts: 5,616
Re: Misaligned Scope mounting holes

Quote:
Originally Posted by Packrat 6 View Post
Howdy all,
I recently traded a nice .308 Navy CMP M-1 Rifle I'd had for years for 2 shotguns, a .38 Special Bullpup for my Granddaughter at College, and a Remington 700 .308 VTR plus $200 Cash. Dan, the guy that I traded all of this for had bought the VTR new with a factory (?) Scope, but had in the last several years had never got it adjusted onto paper. The VTR was essentially new with about 2-3 boxes of shells through it. Dan wanted that M-1 bad and hadn't had any luck with the VTR.

Being smarter than the average Bear, so I thought, I figured that I would throw a set of of Burris mounts and Rings on the VTR and use the Pos-Align rings to bring it back into alignment and have a good Feral Hog hunting Rifle. Not to be!

I set it up, zeroed the scope, took it to the 25 yard range for a 100 yard zero and it was hitting 24 - 26" low left at 25 yards when I maxed out the windage. Thought I had the rings in backward, rechecked the install, no luck.

Changed the pos-align rings to .10 re-zeroed the scope and got to about 14" off the target. Played with various combinations of rings trying to get it even close to the paper. Ordered some .20 rings, but decided I had a bigger problem. Took the whole thing back apart down to the receiver, put a mounting screw in the back Scope mount screw hole and made a loop in the end of some 4 Lb mono fishing line, looped it over the screw and stretched it through the center of the other mounting screw holes and found that the holes were misaligned by about 2 mm to the right, at the bore. (about 26" total length from the back hole) The line intersected slightly the side of the barrel. (Triangular) rather than lined up down the center.

Like some others, I want my stuff right, so the question is: Can a gunsmith screw in some screws, or otherwise fill the holes, grind them off flush, re-parkerize and re-drill and tap new mounting holes in the receiver safely? I've cleaned up and rebuilt a lot of rifles and shotguns, but never run into this, to this extent before, but am sure someone out there has. For some reason, I prefer my scope to be adjusted as close to zero in both directions and I've got a felling I know what I'm going to have to spend that $200.00 on....LOL

Been advised to get rid of it, but am stubborn and won't pass on a problem to some poor unsuspecting LR shooter. Will either fix it or scrap it out for parts.

Any advice is appreciated

Bruce

"The words "Dedication" and "Commitment" are frequently used in the wrong context in conversations and statements The difference is simple: You may be "dedicated" to having a Barbeque, but the Pig is "committed"".

There are several ways to fix this problem. One is to have a smith use a mill and inlarge the site base screw holes (He can bore them with a plunging mill straight and threas them with 8x32 or 10 x 24 taps and then bore out the bases to fit the screws.

Another way is to buy a set on Windage adjustable bases from Leopold or Redfield and install them.
they have a huge amount of Windage adjustment.

Set the Windage adjustment half way on the scope, bore sight the rifle bore, and adjust the rear base (It has the Windage adjustment) until the POI is close and tighten everything up and do the final adjustment with the scope turrets.

years ago this was quite common and the scopes did not have but about 10 MOA of adjustment so this type of bases were necessary.

The only other thing that I can think that might be wrong is the scope may have a problem with the
adjustment or the reticle may not be optically aligned (Now most of the reticles are lazed directly to the lens and could be off).

Good luck.

J E CUSTOM
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  #3  
Old 07-25-2014, 10:24 AM
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Join Date: May 2014
Location: Tucson (Vail), AZ
Posts: 172
Re: Misaligned Scope mounting holes

J.E. Custom

Thanks for the input. If you are a custom shop, then I figure you know what you are doing so will get the adjustable bases. One other problem with most bases is that right now, the scope (Brand new 4-16x) just barely clears the barrel (< 1/8") with the high ( 1/4" +/-) Burris bases. Am going to have to also get super high rings, but this shouldn't be a problem. the rifle didn't come with Iron sights, but may have to get the "See through" style rings to clear the barrel.

Anyway, Thanks again. Didn't realize there was that much adjustment in the adjustable bases. Also, have run into this in a minor way before, but never this severe.

Thanks again,

Bruce
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  #4  
Old 07-25-2014, 11:30 AM
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Join Date: Dec 2008
Posts: 77
Re: Misaligned Scope mounting holes

The Burris rings you mention should do everything windage adjustable bases will do. I would get the .020 inserts and try again, maybe use the .020's in one end and the .010 or .000 in the other, any combination will work to rectify the situation.
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  #5  
Old 07-25-2014, 02:29 PM
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Join Date: Jul 2004
Location: Texas
Posts: 5,616
Re: Misaligned Scope mounting holes

Quote:
Originally Posted by Birdhunter1 View Post
The Burris rings you mention should do everything windage adjustable bases will do. I would get the .020 inserts and try again, maybe use the .020's in one end and the .010 or .000 in the other, any combination will work to rectify the situation.

Not to start an argument but I have to disagree on this one . the Windage adjustable base has over .100 thousandths of adjustment + and may make up the difference . I like the Burris rings but they were not made to correct that much error. (Mostly for elevation help in lieu of MOA Bases).

I personally don't like to use them if I don't have to but sometimes they help to keep the reticle
centered better allowing for max adjustments.

I have never seen a scope in good working order that would not center with these bases.

J E CUSTOM
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  #6  
Old 07-25-2014, 04:20 PM
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Join Date: May 2014
Location: Tucson (Vail), AZ
Posts: 172
Re: Misaligned Scope mounting holes

Thanks for the input guys,

I have already ordered the .20 inserts so will try them first. if I still end up with a lot of windage adjustment in the scope to get it on target, will try a combination of the adjustable bases and the inserts, if it is even possible. I try very hard to keep the scope as close to zero in both vertical and horizontal as is possible and I have quite a bit of experience with the Pos-Align inserts so know to shift different insert sizes back and forth to try and get onto the paper.

The scope is fairly new and worked well (consistent 1 MOA with another shooter, since I have only about 2 MOA eyes, the cataracts being removed in October) on another rifle so I don't think that is the problem.

If everything else fails, will ship it to JE and have them fix the holes.

Thanks for all the input.

Bruce
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  #7  
Old 07-25-2014, 11:48 PM
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Join Date: Apr 2003
Location: North Bend, Oregon
Posts: 1,263
Re: Misaligned Scope mounting holes

Either system will get the scope centered. The Burris inserts are good for up to 40 MOA correction and can do elevation and windage depending on how they are orientated. I like them and use them on everything that isn't getting a pic rail or Talley Lightweights. They are structurally superior to the windage adjustable bases. They do have a place though because they will fix the worst possible misalignment.

Before you go milling/drilling new holes to line things up have the action checked out and see if those scope holes are really out of line with the bolt raceway. Your barrel can easily have this much curve or be threaded crooked. I see factory barrels very crooked when we dial them in for brakes. The last thing you want to do is try plugging and redrilling. That is the very last ditch salvage maneuver.
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