Stanton lost the pistol he signed out of the armory. When I asked him about it he said what direction he went out of the bunker but I wasn't paying attention and what he says didn't save in any notes. Where did he drop his pistol? I'm hating this littel side quest almost as much as the virus one.

This should probably be in the Spoilers section, all I will say here is head for the gap in the fence almost directly opposite and facing the bunker entrance.

Agreed.

...when you find the gap, keep walking. Its farther away than I thought it would be

yea there's a dead body leaning up against a big rock. the pistol is on the top of that rock