You don't.
You can customize all the guns except the ones you pick up on missions.
You need a gunsmith
On battlefield three you can change about anything you want on your guns
I own this app on my iPod and unfortunately you can not customise your own guns
yes
No because a gun cannot be changed by a normal sibling or adult
Your asking about Hy Score pellet guns not Rifles, then most all the Hy Score pistols had a medallion or emblem on the grip.
By using different blue perks, your character will change.
You have to get 500 kills for the silver title, 1000 kills for the emblem (silver) 2500 kills for the White skull title, 250 headshots for the silver title with a headshot emblem in it, 1000 for the gold emblem or 2500 for the Gold skull emblem. This is for Submarine, Assault and Light Machine guns other weapons may vary but just look it up in the challenges section. Hope this helps :)
there is fire emblem radiant dawn,fire emblem shadow dragon,errr, resident evil 1,2 ,3 and 4,metal gear solid guns of the patriots,metal gear acid,starwars battlefront 2.
You get a new emblem and all your guns taken away and you have to start from level 1 and work your way back up again.
The name of the game is Call of Duty 4 Modern Warfare for the November 2007 release. It does not have the capabilities of the later games in the series