I was in the USMC in the early 70's, in LeJuene, in Motor. One Lance Corporal reported that he was working on his truck, doing endless 1st echelon maintenance, when a First Luie came over and asked what he was doing. He didn't really know, so he just muttered, "Aw, shit," and peered out from under the truck. Seeing the butter bars, he of course jumped to attention and saluted. "I'm tightening down the BRT, Sir."
"The salute was returned with a "Carry on, Marine."
I asked him what a BRT was, and he just replied...
"a Big Round Thing..."