It’s hard to say whether it’s the receiver of the rifle or the scope base/ring.
This is the reason lapping and/or bedding exists. The threaded holes in the receiver have to be exact as do the holes in the base. So do the radii of the base contour to the receiver as well as the radii of the rings themselves to the scope tube. Stacking tolerances upon themselves like that is a recipe for being off a little bit every time unless certain prices are paid for extra high manufacturing specs in all of those areas just mentioned.
That seems like a daunting task but in reality it makes small difference most of the time and for hunting purposes, probably not much indeed. More precise disciplines could probably benefit from more exacting build quality.
In the meantime, lap or bed.
You may find out you need to bed the scope into the rings as well or lap them out.
I had an action once where I was able to see the scope base holes in the receiver were drilled off after I mounted a set of two piece Leupold ring/bases (just like the Talleys). I put the alignment bars on and found this.
It was off by a good bit. It seemed like too much, in fact. Sometimes you have to learn things the hard way so I proceeded to lap them in. Halfway through they looked like this.
Something is really off here it would seem. I was in it for a penny already so I plowed forward with the lapping. Got enough contact area and mounted the scope. I went to bore sight it and ran out of windage adjustment.
Crap
Lesson learned. I think I learned something else too. I had a set of single dovetail Leupold bases and rings. The type where you can dial in windage adjustment with the rear ring mount and it can pivot on the front dovetail so as not to torque the scope ring. Well that worked great and was just fine and the customer used the rifle for years (I told him all about it and didn’t charge him for the job) and was really happy with it. Still, the method I used and what I used it for did not make me feel too good.
I never knew what those dovetail scope mounts were for and I still don’t but that is one use.