Checking alignment of scope mounting screw holes

wce323078

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what is the easy way to see if the drilled and taped holes for a scope mount are in line with the bore of a rifle barrel? It seems that the last few rifles I have purchased are way off.Example a Savage Mod10 BAS/T with the factory rail when mounting scope and bore sighting, (with laser) or other bore sighting tools It takes (using burris rings with inserts)a +10 insert at front and a -10 insert at rear to get any where close to the poi.plus about 3 inches of windage and 3 inches of vertical to get to point of aim.I have the same problem with a Win .22 lever action (9422).So Did I just have bad luck in the rifles I got or do the rifles have a problem?I have been mounting scopes for years and have done a lot for friends with my bore sighters and have had no problem getting on the paper at 100 yards.so I don't relly think it is me.Anyone have any thoughts on this
 
Here's my storey. I recently bought a nice Savage 99 with Weaver mounts on it. Went to Wholesale Sports in Calgary and bought a Redfield 3x9 and they were going to mount and bore sight it. After a gruelling 40 minute wait the guy hands it to me and says" there you go, ready to rock and roll". I go to the 50yd range with an 8.5 x 11 target and it hits 1 inch to the left of the paper! After all windage adjustment (there was only 3/4 turn left) it was still 3" left. I'm putting on a Leupold standard one piece base with windage adjustment and never having a rifle boresighted at Wholesale again. The mount holes must be out of line. This is a 1978 rifle with factory holes. Maybe it's more common than you would think.
 
There is a reason why they make adjustable mounts as you have discovered.
I also have 9422 in 22 mag. that if a use a set of Weaver mounts on there isn't enough adjustment in the scope to get it on target. I put another brand of mounts on it and it sighted in just fine with minor adjustments to the scope.
So from that experience I would say not all misaligment issues lie in the rifle. They can make out of wack mounts as well. So I would try some different mounts. I have had several sets of Weaver mounts without issue, but that one set I bought for the 9422 was a bad set as I even tried a different scope with the same results. Those mounts ended up as land fill.
 
Install the bases... with a 36 inch straight edge line up the sides of the bases and look at where the straight edge is in relationship to the muzzle of the barrel, then do the same on the other side of the bases... you can tell if they are not lined up... often a small correction can be made by simply forcing one base in one direction and the other base in the other direction... there is quite a bit of 'play' in the screw/hole fit.
 
I had one rifle with the holes drilled grossly out of line. My solution was to slot the rear hole of a one piece Weaver base, mount the scope, bore sight it, mark the position of the base, remove the scope, and glue the base in place, and tighten the screws. Even though that rifle saw some rough use, the two screws and epoxy holding the base never came loose.
 
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