Need help identifying this large ammo box

[Surpmil]

I used to store my ammo in a very similar can, also of heavy, galvanized steel. The latch arrangement was a lot simpler than that however, just a couple of hook like projections on one side of the lid and closed loop latch with similar hooks on the other side. You hooked the one side in first then pushed down the other side of the lid and pushed it the last little bit by pushing the latch down. A rotating latch in the center of the lid, similar to an old sash window latch then turned over the loop latch and held it down in the closed position. Probably the RN/RCN version of the same container you have. It was very well sealed and naval in origin I believe. Had the same looped carrying handles as yours too.