Gun Nut/Fallout 3

Gun Nut is a perk in Fallout 3 and Fallout 4.

Effects
"You are obsessed with using and maintaining a wide variety of conventional firearms."

With each rank of the Gun Nut perk, the player character gains an additional 5 points to the Small Guns and Repair skills. With all three ranks, the player gains a +15 bonus to Small Guns and Repair.

The perk unlocks a few additional gameplay options:
 * When rescuing Reilly's Rangers, the player can remark to Reilly that they've heard of the organization before.
 * It's one of several options that allow the player to fix Initiate Pek's handgun.

Behind the scenes

 * The image for the perk includes a missile launcher, which is classified as a Big Gun, rather than a Small Gun.