That, BTW, looks far too big for a 100 round can. I'd believe it if marked 200 round. That said, the hundreds I've got measure about 28L x 14.4W x 18H. I doubt 13 cm wide, if that is accurate, would fit .50 BMG; definitely not with the proper packing material (sheets of cardboard) inside.
This said, I've had a lot of success with 40mm ammo cans deploying game stuff around the world. Either the 48 or 32 round cans should serve well.