Being the dumbass cheapskate I am, I thought I snagged a smoking deal on a steel Warne rail on ebay for my Savage 12FV. Turned out it was for an old model 12 with a flat on the rear of the receiver. The 12FV is round front and back. Decided to modify this one to suit. The receiver is Ø1.352", but I cut the rail on Ø1.325" so it would positively touch in 2 places rather than potentially being tippy. Simple hand written G-code only about 25 lines long. It runs a subroutine loop to step over along the cut path. The arc is being cut in G19 YZ Plane. I cut about .003 off the factory end in the same setup to make sure both surfaces were plane and in line.
I screwed up again, and found out the hard way the counterbores were cut deeper on the flat end. I broke through into them. I was able to get some larger headed 6-48 screws and cut larger C-Bores on that end to salvage the rail for the 2nd time.
Moral of this story is I should've just ate this one and bought the correct one. But it worked out and basically only took some time.