>>63897113
I don't know how the British Army does it, but the Swedish Army (what's left of it anyway), has a familiarization practice where they get trained in how to handle common international military rifles such as M16s and AKMs.
Not extensively, but more in the:
>"If you get sent abroad on some sort of peacekeeping mission or something, you should be at least mildly familiar with handling and shooting these common military rifles, just in case you really had to."

I think the Norwegian Army also does this.