ORIGINAL: The Rifleman
The Japanese had about 4 different rounds for their 7.7 Jap rifle in WW II and none of them interchanged. The logistics were aweful, but just think of it like this, even if you captured their weapon, if you didn't have the right ammo - you still couldn't use it against the other guy.
All the 7.7 Arisakas fired the same round. There's no truth to them taking different ammo.