I have never reamed a throat before. Everything I have found says that a HSS reamer costs about $45.00, but it won't do nitride. And a carbide reamer costs about 10x as much.
I just happened to find a suitable 40SW conversion barrel for a project, and it is on closeout for a good price but is nitride coated. About $70 cheaper than what I can find for an equivalent barrel in stainless.
I want to elongate the freebore so that I can load 40SW extra long, and work up some loads for it. (In a 10mm handgun).
How impossible is this idea? I can turn a brass rod to 401.5 in diameter until it just barely slides into the freebore. Then I can put a 10-20 degree shoulder on the end and put PSA sandpaper over that part. Or glue regular sandpaper, if need be. And carefully trim so that it doesn't touch the rest of the freebore.
Then turn it slow with a drill, cleaning and adding a bit of oil, regularly, until my dummy round fits in. Reapply sandpaper and repeat about 1 or 2 dozen times? Or is this simply not possible?
Alpha Wolf barrel, SBN coated RC 60. On sale $119 at Midway.