All of this is 4E, for the record. For my character, a hulking troll ex-black ops specialist, we has two main weapons. Don't have my character sheet on me(I'm at work), so I'll just post the general stats, not the specifics.
Regular carry is a Svalette Guardian, heavily modified with a silencer, High-power Chambering, couple other mods I forget, and a quick-draw holster. He has a license for it tied to his fake SIN(Bounty Hunter) so he can carry it everywhere. Makes enough of a crater that it keeps most trouble away.
Second weapon, and the one he uses exclusively for assassination, wetwork, and assaults, is a really heavily modified Onotari Urban Hunter called E.R.I.C.A.(Extreme Response, Interdiction, and Combat Asset). Gas Vent 2, shock pad, SmartGun(Internal), Underbarrel Grenade Launcher with Airburst Link, bayonet mount, High-Cal Chambering, Manual Easy Breakdown, and an attacheable(read not internal) bipod and silencer for sniping mode. Basically it does almost as much damage as an assault cannon, has long-rifle ranges, and he can set it up for either assault-mode or for sniping from a distance.
As to the earlier question of how people transport their weapon, the pistol is only a Restricted item, so the license covers that. Plus he has a Lined Coat to hide any additional small goodies. The battle-rifle is breaks down after a job and he has a special, really-heavily shielded(radar, wifi, airtight, etc) hidden compartment in his bike that conceals it when not in use. Basically since it's massively illegal he only uses it for activities that are also massively illegal.
But boy does it splatter people when he needs it to.
