I concur.

It came from WW1. The .303 light machine gun (mostly Bofors and Browning) ammo was on leather and later metal (like breakaway bike chain) belts. 9 yards of the belt with bulletts attached fit inside one ammo box. So when the "gerries" were coming over the hill or something/someone really pissed you off, you gave them"the whole nine yards" This usually resulted in the barrel of your gun melting and it was imperitive to unscrew it and toss it before the entire gun was ruined. You'd screw another gun barrell on quick and give the "hun" another 9 yards.

Laying in rat infested MUD for six years and gut shooting folk by the thousands is "fun" like few of us have ever or will ever experience.

Sorry if this fucks up some sexual fantasy.