Extreme windage misalignment question

Katoom · Dec 20, 2020

I am not a scope/optics expert or an extremely skilled benchrest shooter and usually am happy to get everything good enough for hunting out to 300 yards, say around 1.5 - 1.75 MOA. On a recent scope mounting, my initial shot was almost 4 feet to the left and 2+ feet high of point of aim at 100 yards. I did not shim anything and am not using windage adjustable bases so I used the scopes reticle adjustment to bring it back in line. I assume that would pretty much use up most adjustment in the scope itself. I have not had an opportunity to sight in beyond 100 yet, but am curious what side effects of the scope axis being that far off center may be present at longer ranges. Should I start over and try to shim it over somehow, try new bases, etc. Or, is that no big deal to have the scope axis off like that as long as I can adjust it with the dial... and if it is on at 100 will it still be centered at 300, at 500? It’s been a while since I took physics of lenses, focal points, etc, so I’m sorry if this is basic stuff, but I have never had a scope mount several feet off the target before.

coloradoman · Dec 20, 2020

I had a buddy that had the same problem after buying nightforce but it wasn’t the scope it was a gun he took it back and they replaced the gun at no charge and he’s is good to go now

Katoom · Dec 20, 2020

i know the scope is fine, I had it on another gun. But the new gun and new base, certainly one of them seems to be drilled off-center, not sure which yet.

Cahunter805 · Dec 21, 2020

It’s more than likely the action scope base holes are off center. Have you checked ring alignment? You could probably get a lot closer to center with a light lapping of the rings also.
It might be an issue if your going to be dialing with this rifle/scope. I prefer to have plenty of adjustment especially elevation.
What rifle and scope base/rings are you using?

Zeke · Dec 21, 2020

We pay money to be able to reach 20” height at 100 (20 MOA rail) so 24” high doesn’t alarm me too much BUT the 4’ left at 100 yards seems like the base holes on the action are way off or maybe the barrel shoulder, action face is way off and out of alignment.
Like cahunter85 asked, “what bases and rings are you using?”.
I’ll add, what action is it?

Zeke

hawkbill · Dec 21, 2020

I’d put 20 MOA bases, and try resetting bases and rings

Katoom · Dec 22, 2020

Using Leupold weaver rings on stock base of a Ruger American .308. I had removed the base and reinstalled it to ensure proper torque so I feel it was aligned as good as it could be and certainly not loose. This is no custom gun as you can see so a factory misalignment in the holes or barrel seating is not out of the question. I am still interested in thoughts on the optical axis not aligning with the barrel axis, and what effects that may exacerbate at distance. That said, it is probably best if I just replace my rings with ones having adjustable windage and getting my zero close without having to take up the slack on the dials.

By the way, the rifle shot excellent groups at 100, and not just for a $400 rifle, but about as good as anything I have. As stated, I don't aspire to have every hunting rifle inside an inch but this one was there easily (once on the paper), with factory ammo using Swift Sciroccos.

Cahunter805 · Dec 22, 2020

I assume you mean the leupold PRW style rings. I’d try another set of rings and see what happens. TPS, Seekins and Hawkins make some very nice rings. A couple decent cheaper options are Burris signature or the vortex precision. Check Amazon.
Also I’d recenter your scope before mounting it again.
When securing the rings did you tighten the base screws one at a time or swap back and forth front and back tightening each a little at a time?