Machining a Smaller Radius on a Scope Mount to Fit Barrel Properly.

I had to machine a smaller radius on this scope mount so it would fit a 22 rifle barrel properly. I used a ball end mill for this operation.
102776 16.0mm Diameter x 16mm Shank 4-Flute Regular Length Ball Nose Blue Series Carbide End Mill
https://amzn.to/3X2vjgb