This may seem to be a dumb question, but I have never found the answer anywhere else.
Why did the British list their tank guns, artillery, etc. in pounds, i.e. 17-pounder, and not mm like everyone else? It’s just something that has picked at my curiosity for a while.
Tradition. Naval and land muzzle loading cannons were always identified by shot weight so I guess the custom continued. Not all British guns use shot weight, as they get bigger they use the calibre (in inches i.e. 3.7" AA, 4.5", 5.5" & 7.2").