its just a weird thing with his mechanics and dramatics, but its really awesome, actually. I've got a rule in me head called the 'Aggro Exception', meaning you can bluff ranges when a character is going aggro, cause its one sided. But when you're seizing their whatsits by force, in an alley fight, in a stairwell, the first floor of a ruined parkade, the handgun comes to bear faster and more accurately than the rifle. Dramatically. But the vice versa of course is true, Sarajevo Joe will pick you off with his rifle, and you won't have a chance to draw your six shooter and make much good of your threats, until you make it up the stairs that is, and then of course ...
it keeps different choices valid, plus it makes the MG, one of the gunlugger's specials, and the battlebabe's mod which you were referring to, well it keeps them special. Otherwise there would be inflation from everyone getting that kind of range, and then the gunlugger would need an even bigger board with an even bigger nail in it.
i personally added hand range to derringers and sawed-off shotguns, to keep them ugly and surprising and in your face. Also added intimate to knives, cause you can stab someone in bed, but you can't swing a golf club or machete without them noticing, citing, of course, my previously stated Aggro Exception.
i kinda had a hard time with the naming of some of those mods myself, like why auto and semi-auto do such different things, so just rename them, call them extended clips or bullpup conversions or stock and barrel mods or whatever, it won't change the function, just the flavour. So long as your MC is cool with it.