Crazy idea that might make shotguns a bit more popular and useful...
sports rifles, sniper rifles and assault rifles are all designed for relatively long engagement ranges, and can be unwieldy and more difficult to aim in close quarters. So rather than just giving them longer ranges, why not give the guns different sorts of range penalties as well.
For example
Short Medium Long Extreme
Shotgun +1 -1 -3 -6
SMG -0 -1 -3 -5
Assault Rifle -2 -0 -2 -4
Sports Rifle -3 -0 -2 -3
Sniper Rifle -3 -2 -0 -3
Obviously that's very crude and it would be hard to balance (and make things more complicated, but it might make SMGs and shotguns more worth taking other than just for concealibility. Afterall, their purpose in military use is closequarters combat like room clearance. The sort of thing I'd have thought runners actually do quite a lot, and I'd normally expect them to be a smart runner's preferred weapon, logically.
But then I'm a brit, so I know sod all about guns.