I'm curious actually where the UK draws the line on gun parts. A barrel, for example, is a pretty specialized part that isn't too hard to recognize as a gun par

I'm curious actually where the UK draws the line on gun parts. A barrel, for example, is a pretty specialized part that isn't too hard to recognize as a gun part, and isn't useful for anything else. A lot of other parts are simple little bits of machined or stamped metal, though, or stuff like springs. If I mailed somebody in the UK a barrel, I assume it would be found and everybody involved would get in some sort of trouble. What about a spring, though? Would anybody get in trouble if you were mailed a spring? Can then even tell whether that spring is the mainspring for a 1911 pistol, or a part for a pressure valve at a factory or something? How about an AK trigger guard, which is a funny-looking bit of stamped steel? God only knows what some random person seeing that would think it's for.