Sorry Krusty, but I think I'll take the word of ASA, and people who were in the war,Geoffrey Wellum, Mr Edds dad, My grandfather, and many more, over you.
The machine guns of a P-51 Mustang were fed by ammunition belts that were 27 feet long. After a pilot emptied his guns on a target, he would say that he "gave 'em the whole nine yards"
here is where I recieved my information, One of the highest respected Aviation knowledge companies.
Test Pilot- 1,001 things you thought you knew about aviation. Berry Schiff .. Aviation supplies & Academics,. inc Newcastle, washington 2001