Scope mounting/bore sighting question

[Toddmonty]

I have a GA Precision .280AI with the Templar action, GAP mounted scope base that indicates it's mounted properly like one would expect.
I have a Vortex 6-24x50 PST SFP MOA scope with Vortex precision matched rings. Made by Seekings or someone I'm told, but they are true & didn't need lapped.

After mounting on rifle & bore sighting with laser at 100 yards, my vertical adjustment was dead on with turret bottomed out. So I loosened turret & reset it to "0", tightened up, ran it up & down several times & it kept coming back to zero on target.

Then I went to horizontal turret & reset it to zero. I only have 5 MOA movement to the left & over 20 to the right. Adding the shims would make it less to the left, same to the right.

Is there something I need to know about??????

I hope I don't get the "Most stupid question of the year award".

 

[shovelstrokeed]

For me, I would first question the laser bore sight and then, if that proved to be dead on, the mounting of the rings to the rail.

By reputation, not personal experience, I would probably be willing to bet good money that GAP put the rail on straight. It sounds like you may have a 20 MOA rail on the gun though, check with GAP.

A quick trip to the range might be revealing. Remember, a laser has no trajectory, a bullet travels in an arc and right on the money at 100 is really probably wrong.

I use a laser bore sighter to get me more or less on target but I have really not been able to dope out the difference between my scope height and the laser to get my elevation where it needs to be, it usually gets me within a click or 3 on windage though. I have a muzzle device of one kind or another on my rifles and that can cause my stick it in the muzzle laser to be off by quite a bit compared to my scope. You have to get the thing far enough down the barrel so that when the taper matches up to the bore at the muzzle the expanding part is far enough down the bore that the alignment with the bore is assured.

Best bet is to pull the bolt and peer down the bore at 25 yards with a nice fat target to work with. Center the rifle as best you can and then check the crosshairs. With the 280 AI, your bullet should be about 1" high compared to the scope crosshairs. Fire a couple of shots and then move the crosshairs, without moving the rifle, from point of aim to the center of the group. Do the same again at 100 and you'll be right in there.

 

[Toddmonty]

Yea, I only use the bore sighting to get me on the paper too. It just seemed a little off on the horizontal adjustment based on my past experiences. I agree, once I go to the range, it'll be a true test to see if I have an issue or not.

If one would have the horizontal issue, what do you do next?

 

[shovelstrokeed]

Might be a PITA for you but I would look at the fit of the rings on the rail.
Picatinny rail and Weaver rail are not the same thing. Also, do the rings really seat down on the top or are they being held proud by the cross screw. A strong flashlight and a little time might be revealing. You might be able to see something by removing the upper half of the rings, leveling the action and then comparing that level with a level across the portion of the rings still attached to the rifle.
I can't do that with my Spuhr mounts as the ring clamps are at an angle to the rifle. Another quick thought, are there equal gaps at both sides of the rings where the scope mounts. It should not result in a 15 MOA difference in available windage but you may want to check everything.
There is just something about this that tells me your scope is either mounted at an angle to the line of the bore or offset from the line of the bore. Again, I'm pretty sure it is not the attachment of the rail to the gun. GAP is just too good to get that wrong.