I cannot find a good place to call level on the receiver of the weapon to start my scope mounting.

Rifle is in a solid jig and does not move.

Level the rifle at the most forward lug of the receiver and lock it in. In theory this should be level to the bore, correct? Wrong. Using both a verified level and an angle finder as I move to the next lug in the rail it becomes off by 1 degree and continues to grow as I get closer to the charging handle. Meaning about every 1 inch the "level" changes.

I have three 15-22s and I have confirmed this is the case on all of them. Looks like a quality control issue during manufacturing.
All these weapons are new never fired.

The question is: What are you doing to fix the problem? If the the base that the scope mount sits on is not level to the bore then how will the scope ever be plum of the axis?

How are you determining the bore is level and plum before mounting scope?

Thank you