[m&p45acp10+1]

I have a friend that works down the street a machine shop. They have great measuring tools there. He will mic a few for me. As well as a pure lead round ball that I used to slug the barrel with today. I checked the caliper against 10 Laser Cast 350 grain sized at .459 all of those were .459 on my caliper.

Oh and for the micro grove rifling. I am looking down the barrel, and the rifling does not look shallow at all. It is deeper than most of my hand guns, and several of my good shooting rifles.