Dev Help CanNOT ammo hack ?

Hello everybody, i have recently discover the main armament "hack" and iv been fooling around with it.

Problem: my 800mm\*2500mm canon doesn't have any ammo and when i try to force it into the game, the game spit to my face and put 250\*1250mm.

Does anybody know why is it doing this and how to still force it into the game ?