Gun colour won't make any difference to your play, but it does enable trained observers to make comment on the your skills, abilities and personality
Black - tight fisted, didn't want to spend anymore money than they had too, intrinsically evil, back players or students
Rusty Black - You must be Tiny from Dark Ritual
Red - Angry people, little or no skill, try to scare people away with bright colours
White - Muppet
Blue - cool, laid back, sneaky
Silver or Gold - ponce, tart, more money than sense, little intelligence or wisdom
Green - oh dear, long term sedimentary illnesses, no close friends, wishes he could wear camo again
Orange - either sponsored by a telecomms company or see White
More than one colour - not to be trusted, liable to have personality disorders