This seems a bit strange, since it's the length of a long gun that makes it more accurate and deadly. I thought maybe the fear is that a shorter gun is more concealable, but that doesn't make a lot of sense in a world with the Desert Eagle. Shorter shotguns are popular in the military for being maneuverable in close combat, so I suppose that could work to the advantage of criminals too. Probably best not to evaluate gun law on the basis of what makes sense. Michael Mann seems proud of his sound in "Heat", and the echoes booming in the L.A. canyons along with the tinkling of shell casings was eerie somehow. At least the guns don't click and rattle like someone walking through a pile of coat hangers every time someone handles one. (I assume that's the right link, I must resist the gravitational singularity of TVTropes today.)A sawed-off shotgun is specifically called out as a Title II weapon of the National Firearms Act.
most of what you see in film is synthetic foley
Sawed-off shotguns are as illegal as machine guns because there's no sawed-off shotgun lobby to make them legal as handguns. https://www.quora.com/Why-are-sawed-off-shot-guns-illegal It could be argued that they have a wider pattern but yeah. It's not like lopping off the barrel makes them deadlier. The sound in Heat is pretty dope. It's not like all movie guns are bad, but the good ones don't really get noticed unless shit's fuckin' legendary.
Back a million years ago in the days when I hung out with, um, "interesting" people I was given the opportunity to fire a shotgun with a 12" barrel. Absolutely not legal, not at all. Here is the thing about that gun: with its home made pistol grip it fit perfectly under a coat and was not that much bigger than one of the stupidly large bore handguns that were popular a while back. Put slugs in that gun and they went through walls. It also recoiled like a mule. Fire buck shot in that gun and everything in a 90° arc in front of you got hit by something, which is good because your arm is now pointing up and I took a few seconds to get the thing back level again for the second round. My guess is that the wad pushes the pellets out in a wider cone with a shorter barrel, but it has been forever and I'd have to look up someone who has video comparing a longer barrel to a shorter one. I've owned guns, am currently around army people who live guns, and went with a few friends to this exact shoot. I'm probably in some of the video from the early evening rounds where they were just firing machine guns; we stayed for the tracer and cannon fire because I like firearms, tangentially, but these nuts? Lots of GOA stickers. For the uninitiated, the GOA, Gun Owners of America, is an off shoot of the NRA who thought that the NRA was a bit too liberal and tolerant for their tastes.
Thing is? These ain't Class II NFA weapons. Back in the '90s you could buy them mail order - if I recall they were like $20. And I guarantee their pattern is less choked than a sawed-off. There are youtube videos of patterns for 16" barrels, 12" barrels and 22" barrels and up close'n'personal they ain't that different. Here's a .410/.45ACP over/under pistol. sawed-off shotgun legality has a lot more to do with vintage caselaw than modern lethality.
It is, and at least in the case of the post-bank shootout, it's because Mann specifically refused to use the version where the sounds were replaced. It was all recorded on set.The sound in Heat is pretty dope.