No need to break anything there... The ZU's 23mm ammo comes in an old fashioned way; ammo in one box and the links in another. The links are singles, you attach them together to form the belt. The ammo holds the links from separating, and after it cycles through the gun, the links come off again (so that a continuous chain on links wont choke the system).
The only thing that sucks a bit in this system that without a proper machine designed to push the ammo in the links (or out of them), you will have hard time to make or break the link... hammering the shells isn't the best idea, but that is known to happen in certain less civilized countries