>>64471691
>I'm personally not sure how you cut that without putting a burr on the edge or making the edge all wavy or kinking it.
You use a break, and yeah feeler gauges are great. What else is great are high grit diamond stones off amazon. Those coupled with some polishing compound are what I use to fit all my retarded shit. It's amazing what you can do with a set of go/nogo gauges, scrap metal, a drill press, and some balls. I'm looking to get a 3d printer next just because it will cost less when I hopelessly fuck up a receiver/frame.