one half inch is 50 cal or 12.7 mm. [25.4 mm == 1 inch] there was an issue with the desert eagle as a 50 cal weapon, at time considered a DD, so there was a r

one half inch is 50 cal or 12.7 mm. [25.4 mm == 1 inch] there was an issue with the desert eagle as a 50 cal weapon, at time considered a DD, so there was a revision for civilian carry that was, 49.5 cal with a tapered chamber. if bored out to a true 50 cal, it would constitute production of a DD i think i was looking at the 20mm cannon as well https://news.ycombinator.com/item?id=32957960 https://news.ycombinator.com/item?id=32957960 but posted over here.