I am sure that we all have run into them before. You the guy. He is in his early 20’s and has done it all. Been in some top military unit but does not know what a MOS is. Also has shoot every type of gun known to man. Yada yada, yada, right?
My favorite one was the kid at the local shop. Who told my son that he didn’t need a timney trigger on his rifle. Just put some more oil on the trigger assembly. (A major No, No by the way)