Padeye is dead on about the 1986 Machine Gun ban. Any personally or corporate owned machineguns had to be registered before 86 (if they’re american) or 1969 (if they’re imported).
There are a few misconceptions people have about owning machineguns in general, and I will try to clear them up.
A person does NOT need a CLASS III license to own a machinegun. Provided it’s pre 86, the citizen only needs to fill out some registration transfer paperwork and pay his 200 dollar tax to the ATF. Then he gets a Tax Stamp saying the machinegun is legally his. This, in theory is all it takes to buy a machinegun. But some shitty places like California or whatever will be more strict about things. In some places, citizens need to use the “Corporate Loophole” to get their hands on fullautos. So then they’re corporation buys it, instead of them. This gets past the hurdle of needing a judge or sheriff to sign certain forms that sometimes the Sheriff will refuse to sign - cause he’s an asshole.
…moving on…
The CLASS III license that everyone talks about is a Special Occupational Tax that, along with the Federal Firearms License, allows a person - most likely a BUSINESS - to sell machineguns. The CLASS III is intended to let people SELL machineguns. That’s what it is for.
Obviously, some people get their hands on these licenses who have no intention of selling anything. Or maybe they occassionally buy and sell something for a quick profit or whatever. But the big advantage of having the CLASS III is that you are no longer limited in the kind of machineguns you can possess. A person - as an agent of his company that holds an FFL and SOT - can possess modern machineguns. He can buy, sell, and possess modern M4s made last week, and MP5s made last year.
The restrictions, though, is he has to get rid of all his machineguns when he gets rid of or loses the license. (If you are knowlegable and you know about PRESAMPLES… just let it go 
- for our purposes here, we’ll say that he gets rid of all his machineguns)
The ATF, in a move to crack down on people getting SOTs simply to possess machineguns, have made transferring fullautos on a Class III more difficult. Let’s say I have a Class III dealer license and I want to get a brand new HKG36C. Not only do I have to find one and pay a lot of money, but I also need to produce a “Letter of Intent” signed by a Sherrif or Chief if Police or something stating something like:
To whom it may concern:
The Backwoods Police Department is interesting in purchasing new G36 weapon systems and we would like to see a demonstration of the weapon from Nenno, Inc.
If the department decides to not buy the weapon, I am still allowed to keep it in STOCK.
So you can see that all a person needs to do is get friendly with the local sheriff or chief or something or pay someone some money for a letter of intent. And when you’re rich enough to be spending 50,000 on machine guns, you’re rich enough to get your hands on a simple Letter of Intent.
I was sold two Belt Fed HK21Es to a Pediatrician up north who had an FFL and SOT. Weapons were just a hobby for him. The cost was thousands and thousands of dollars!!
He had a letter of intent from a police department that basically read like the Doctors wish list of weapons. It had like three dozen rare weapons and things everyone is trying to get his hands on. It had shit no police department would ever care to get. But it was a letter of intent and it was official.
Most peoples’ Letters of Intent look just like that. Like a wish list or shopping list.
So I hope that clears some things up. By Federal Law, any nonfelon citizen can buy a machinegun. There are certain limits to what machineguns can be purchased though. New weapons are forbidden. But a license is not needed to buy or possess it, just a Tax Stamp. State and Local laws make this process more difficult.
The Class III LICENSE is a dearler’s license and allows a person (with minimal hurdles) to build a collection of pretty much whatever machineguns he wants and can afford.
This does include MINIGUNS. If he gets the letter of intent and can afford the damn thing, a person with a Class III can buy a brand new minigun!
I’ve only met one man who owned a minigun… actually two men, because I met the guy he sold it to. I will tell you how he got it. He had a Class II Manufacturer’s license and is able to make machineguns. So he MADE a minigun. The thing was bad ass too!! It was attached to the rear of his truck. It would slide out and swivel around and there was a little chair thing… man it was awesome. There were two rows of car batteries in the bed of his truck and two 5,000 round ammo boxes. It was really nice!!!
He later sold the thing to another guy who had a CLASS III. That guy didn’t mount it to his truck though. He figured it looked much better on top of his APC!!!
Man… I miss my old clique!
Hope that cleared up a little bit.