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Bore Alignment Trouble.....Help!

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Old 10-03-2002, 09:08 PM
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Join Date: Sep 2002
Location: Illinois
Posts: 836
Bore Alignment Trouble.....Help!

I have a problem with a custom 98 that I think revolves around scope base holes being out of alignment with the bore. Let me back-up a bit and tell the whole story if you please. Last weekend I went to a local club that happens to have a 1000 yd range. One of the rifles I took was a 30-06 Ackley, a very nice gun that I waited almost two years to fire. The smith put standard Leupold mounts and rings on it and I ran out of elevation, but could still get it on paper. I came home and ordered a tapered base and Mk IV rings. I carefully assembled the whole works, mounted the scope which happens to be a Leupold, walked out the back door to the rest and fired a round. No hole on a 2'X 3' target set at 100m. So I pulled the bolt and centered the bore on the target. As I then looked into the scope, the dot was about 3' to the left of center paper. I thought this can't be right. I then removed the windage cap and turned the adjustment to the max, realigned the bore on paper and looked through the scope. This time the dot was only 2' left of center. I chambered a round, aimed at the left edge of the target stand and squeezed. When the smoke cleared there was a hole in the far right of the paper. I fired a couple of more just to make sure it wasn't in the scope, it wasn't. I then called the smith and told him the problem and he said it sounds like the tapered base is bad, but he would like to see the weapon. I said I'll bring it out. FYI, the base is a Ken Farrell tapered one piece base, a real nice piece to say the least. Scratching my head, I picked up the Leupold base that came off this gun and I noticed the windage adjustment screws were uneven to the tune of 3/32nds of an inch greater on one side. It is so far out of wack, the front ring is even angled in the base. The question I now have is how do you fix this? Is there room to just redrill the holes and try again? Is there a way to accurately align the base holes with the bore, maybe a lazer device or something? Any suggestions would be much appreciated!
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Old 10-20-2002, 06:08 AM
MAX MAX is offline
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Join Date: Sep 2001
Posts: 263
Re: Bore Alignment Trouble.....Help!

Sometimes this can be addressed by with shims, depends on the amount of offset. However it sounds to me like you're looking at a weld repair and new installation, ie. fill the old holes and start over. If you're going to peck away at 1000 yards you need to be optically centered to start with, or at least pretty close... It is possible that only one end or base is out of alignment. A Thorough examnation is in order.
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Old 10-20-2002, 07:01 AM
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Join Date: Jan 2002
Location: Wenatchee, WA
Posts: 804
Re: Bore Alignment Trouble.....Help!

I don't know if I can help, but I've got a similar 'problem' that is about to drive me nuts (short trip, I know).

I did some trading and ended up w/ a Sightron SII6-24x42D from my neighbor. I know he'd never had any problems w/ it per se, but then he was more the kind to sight the scope in, and then just use hold over and Kentucky windage for correction from there. Nothing wrong w/ that for what he wanted it for (varmint/predator hunting), but I was looking more for a scope to stick on my .308 Win for F-Class matches, where considerable changes in elevation and windage are needed, and holdover probably isn't going to cut it. I picked up some Burris Signature rings w/ +/- 0.010 inserts, thinking that btwn the ~60MOA of the scope, the 20MOA of the Badger Ordnance one-piece picatinny rail, and 10MOA from the inserts, I should be able to shoot about as far as a .308 can stay supersonic and be reasonably close to centered optically.

Problem was, when I mounted the scope, it was pointing off to one side as viewed thru the borescope. I ended up using almost all my elevation trying to get it 'centered' ( I realize boresighters like that are imprecise at best). Shooting at the range, though, proved the boresighter correct. So I had to use the 10MOA inserts, rotated 90 degrees, to center the scope w/o using up all my windage on the scope. Had some other issues w/ the scope, and had the local gunstore (Sightron dealer) send it back. They would have exchanged it on the spot, but they didn't have one like it on hand. After about 7 weeks, and a *lot* of badgering about WTF my scope was, they handed over a new one that they had ordered for inventory, as 'mine' hadn't shown up yet. Brandie-new, in the box and everything.

Got it home this weekend, and went to mount it on my 40XB, w/ Leupold QRW bases and rings. Guess what? Damn thing is off center, about the same amount. Popped the current scope off the Badg Ord rail on the .308, and tried it on there. Even more off, if that's possible.

Just to point out, before anyone asks, yes, I've tried multiple guns (Remington 40XB, 700VS), multiple bases (Badg. Ord one piece 20MOA, Leupold QRW two piece, Leupold one piece 15MOA LR, Leupold two piece Redfield-style), multiple rings (Leupold QRW, Burris Signature w/ and w/o offset, Leupold Redfield-style), and nothing really changes. Sure, a small amount here or there, probably due to machining tolerances btwn the various components, but nothing significant.

Never had a problem w/ these guns/rings/bases w/ other scopes. I *do* have one gun, a 700VS, that requires the use of Redfield-style bases (rear windage adstable, front dovetail), since the base screw holes aren't lined up. Found that one out the hard way when I tried switching to Weaver style bases. I really am not enthused about having to use a windage adjustable base (due to eye relief issues) to compensate for a jacked up scope. I just can't believe that I got two in a row that were hosed exactly the same way.

Can anyone spot what I might be doing wrong?


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Old 10-20-2002, 07:53 AM
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Join Date: Sep 2002
Location: Illinois
Posts: 836
Re: Bore Alignment Trouble.....Help!

Thanks for your replies. To make a long story short, I returned the gun to the smith and he reindicated the holes on on his mill and found them to be off. The holes were remilled, drilled and tapped and problem solved. He also enlarged the base holes for the larger mounting screws. By the way, there was a smith named Bill that had previously corresponded with me, would you please email me once again for Yahoo completely deleted my email for unknown reasons and you were lost.

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