Quote Originally Posted by gute View Post
My question has to do with the Ground Combat Vehicle and arming it with a 25mm cannon and not something bigger. Could these type of experiences in Iraq had something to do with the idea of arming the GCV with a 25mm cannon?
Other armies went from 30 to 40 caseless (UK), from 20 to 30 (Germany), added a 100 mm next to their classic 30 mm (Russia) or kept using something in the 23-40 mm range. Most IFV purchases of the last few years appear to have been about 30-35 mm main guns.


I suppose the U.S.Army simply stuck with what's established in its training and ammunition stock system. I have yet to see or meet any source claiming that 25 mm is optimal. The problem is that the autocannon calibre choice is a choice between the devil and the deep sea. It's unsatisfactory in some regards, no matter what.
25 mm does not chew or bite easily through walls unless you use expensive APFSDS, and that's messy in infantry support because of all the sabots. 35 or 40 mm doesn't allow you to carry many rounds. Telescopic ammo such as used by the CTA 40 is more compact, but you could still carry more if you stuck with a smaller calibre.