A field gunner is a former member of an 18 man Field Gun team. The sport of Field Gun was played by the British Royal Navy up to 1999 and commemorates the Royal Navy involvement in the seige of Ladysmith, in 1900.
The sport involves a complete 12-pounder 4.7 inch field gun and limber, total weight 2100 lb. It has to be taken to pieces, moved over two 5 ft high walls, a 28ft wide chasm, and through two narrow openings that are each just big enough for one man to crouch and scramble through.
Then it has to be reassembled and fired three times before being taken back down and carried via the same obstacles back to the start line.
The only extra equipment allowed are two spars and a wire to make a sheerlegs crane to get over the chasm.
The average time for the entire run was around two mins 30 secs.
Nowadays it has been revived as a game for kids, so is not the same thing at all.
A traditional Field Gunner is therefore a hard-assed motherfucker who never thinks about injuries and pain, and a true son of a gun who you would love to have on your side in any confrontational situation, and who will have a good laugh about it with you afterwards in the wreckage of your wannabe assailants.
I'd fuck her at the drop of a hat. But her brother is a Field Gunner so I'll ask him if I can date her first.
Cheerful Charlie: Fuck, man, you've got no fingers or thumb on your right hand! Are you a Field Gunner?
Bollocky Bill: Yeah. But I've still got a complete set left.