AMX-13 a French built and obsolete light tank.
http://www.army-guide.com/eng/product1390.htmlThe Russians did it too, but this was one of the first to witness the utter fail that is an autoloading tank. Slower load time, this one had to elevate the gun in order to reload the magazine, one less crew to pull maintenance, ammo not isolated in a mag=Bad News Bears when something hits you.
Edit: It's been a few years since I was really up on tanks. From the link:
Once empty, the magazines have to be refilled by hand from outside the tank. The gun fires fixed APC and HE rounds.
Oh who is going to volunteer for that job?