Well, I skipped a step and posted somewhere else before here so I figured I should fix that.
Im an experimental machinist for a research university (the university used to be featured on mythbusters pretty often). Working at the university Ive had to make numerous sabots to adapt everything from a 120mm to a 20mm sabot, to a 20mm to .75 sabot. Ive also had to throat a couple cannons, crown a couple cannon barrels, make fixtures and internal parts for a 16 inch recoil-less rifle, and make internal parts for a BLU109.
After doing all of that work on the universities guns Ive decided I want to do my own gun work want to start turning my own barrels and making stupid wacky rifles that have no reason to exist. For example we have an few gaylords full of 20mm vulcan brass that I want to neck to 408,375,338,6.5, and 6mm just for giggles.