so. there are a couple of issues here, one is easier than the other...
I'm guessing you want a machinegun. has come up a few times before. allowing multiple shots w/ rifle or deagle is easy. that's just a property in the weapon definitions in the game source.

allowing multiple rapid repeated shots is a little more complicated.

right now, if you shoot a hog, he only gets damaged once, then while he's rolling the bullet flies on to damage other hogs. that's 'cause the code in question only hits not-moving hogs. but a machine gun bullet should be able to hit moving hogs, and ideally from roughly the direction facing the gun.

there's a function for damaging anything, including hogs in motion, but you also need the bullet to only hit a hog once, then fly on to hit others.. for that, some sort of tagging or list system is needed.

that doesn't exist yet.

there've been people who have expressed interest in this in the past, but no one who has sat down and done it. and, as noted in the other thread you started, I'm a bit more biased towards unique utility/weapon options than straight line of sight damage dealing.