None other than a soldier
As a newly commissinaed infantry（步兵） lieutenant, I was eager to set an example for my platoon（排，团） by cleaning my own M-16 rifle. While we were working on the weapons, one soldier complained about the unusual notched（有缺口的） shape of the M-16's bolt and chamber, which makes it difficult to clean.
"Lieutenant, they need to make something to clean this with," the soldier said.
"They do," piped up（开始吹奏，高声说话） a sergeant.
"Really," I said with surprise, wondering why we had not ordered such a tool.
"Yes, sir," replied the sergeant. "It's called a soldier."