>>64127319
Movie armorers are batshit insane. Case in point: Albert Pyun's guy. Made the Underworld guns, chopped a fucking 20mm AA cannon down into a rifle, duped the Smartgun with an M60, does absolutely unholy shit with Mossy 500s like mocking up rotary grenade launchers on them. Or that sick Bulgarian fuck who had a bunch of Colt sporter parts and welded them onto a chopped-up AK to make "M-16s".
If you're asking about that movie/gun in particular it's a Calico 9mm SMG converted to a carbine with the 100-round drum attachment and a bunch of plastic added. It's been re-used in a couple of movies and I'd stab someone to get my hands on one.
https://www.imfdb.org/wiki/Wrongfully_Accused#Submachine_Guns

>>64110972
Less than you'd think. If you're a big dude you can carry one on a sling at the hip (pic related), you'd only need the waldo to be able to eat the recoil. Call it ~100 lbs or so for ripping off a full belt, maybe 150 if you really wanted to go to town and carry some ammo

>>64135739
I hope he at least bought a few of those Berettas and lived the dream.