Continuity mistake: The second time we see McGee bidding on clubs there is 1m 24s remaining. 3 seconds later he closes the window when Gibbs walks in, and there is 1m 24s still left. (00:21:00)

Continuity mistake: When Gibbs asks the kid where he got the gun, he has a notepad in his hand. Camera cuts and it's now a pen. (00:05:25)

Continuity mistake: When looking at the playboy magazine at the start, the pages change between shots. (00:01:50)
Chosen answer: "Policing your brass", means to pick up your expended shell casings, after firing your rifle, or pistol.
pross79