How shell weight limits rotary magazines

What is the largest shell size for which a rotary magazine would remain practical?

Cruiser calibers, perhaps around 9.2 inches, are the suggested range; larger shells increasingly strain the system because of their weight.

A suggested upper range for rotary magazines is cruiser-caliber ammunition, around 9.2 inches. Larger projectiles might be possible, but their rapidly increasing weight becomes the obstacle. The estimate invokes the cube law to explain why small increases in caliber impose much larger handling loads. Wartime shell-handling experiments included mechanisms resembling arcade grab machines as another way of moving heavy rounds within magazines.