You spend more on accesories for your gun than for your wife
If you (annoyingly) comment on guns as they appear in movies. "That gun doesn't make that sound" "Oh, that's a gen2 glock 17, see the lack of finger grooves... well, it could be a gen 2.5, but you get the idea..." "A .45 wouldn't have that trajectory" etc.
If you find yourself trying to find the lump on random people's sides to see who's carrying
If people at work call you the gun guy