The guy at the gun show selling once fired brass that clearly was not

[mazerunner]

You can spot it if you look closely. The primer pockets feel loose, the necks have that worn gray look and the headstamp looks like it has seen more than one cycle. Some of that brass was on its last leg. It was a good reminder to inspect used brass like your hands depend on it, because they do.

 

[Jlogic]

That label means very little in the real world, the brass itself usually tells you its real story with a quick look and feel.

 

[Alan]

Gun show once fired brass always comes with the implied second opinion...your calipers and your eyeballs.

 

[Mordockk]

Once fired at gun shows usually means it lived a full previous life and then some, so always inspect carefully