smooth bore long guns

[USAF_Vet]

I have designed a few 'WROL' type guns a la Peter Luty and his British Standard Pipe sub machine gun. Obviously his design is highly illegal in the USA (and in his native England) as an open bolt, short barrel, full auto, newly manufactured machine gun. His design is also a smooth bore, which I know is illegal for home made pistols (without an NFA stamp to manufacture an AOW) but what about long guns?

On paper, I've designed a semi auto gun firing from a closed bolt that can be manufactured using a few basic power tools and hand tools. Im at the point where manufacture of the design can be started, but my barrel is smooth bore. I could build a rifling jig and throw in the lathe at work, but that defeats the purpose. The BSP, like the STEN before it, was essentially a last ditch gun that could be mass produced as quickly as possible using as little as possible, and my goal is to replicate that with a US legal design.

The smooth bore is my road block. If it were designed to feed a .410 shot shell, I'd be good to go, but as this design is for a .38 special, I need to know if a smooth bore is okay. I'm assuming if it is legal, it will need an 18"+ barrel. If rifled, however, 16" would be the legal mark.


On paper, I initially designed it as a convertable handgun with the option to add a stock and a quick change long barrel, but scrapped the idea until I can figure out a simple 'garage gunsmith' barrel rifling system.

 

[BHP FAN]

Why don't you use a barrel made with barrel blanks available from Gunpartsco, or Shotgun News? Not everyone has a lath, but a chamber could be made with a hand drill and a collar that limits the drill depth, in a pinch.the blanks come rifled, so you'd be keeping it legal, I think.

 

[MErl]

Just treat it like a shotgun and go with an 18" barrel minimum. Shotgun rules are smooth bore fired form the shoulder, nothing about the shell they fire.

http://www.law.cornell.edu/uscode/text/18/921 (a).5

 

[USAF_Vet]

Thanks Merl, that's what I was looking for.

BHP, I could buy the barrel blank, but that would defeat the purpose of the project.

 

[justashooter in pa]

make sure it has the clear and obvious appearance of a gun. if it does not look like a gun it could be ruled AOW. that being said, ATF has already ruled that simple shotguns made from plumbing pipe are legal as long as they nave an obvious pistol grip and reqisite length.

 

[USAF_Vet]

Yeah, it will look like a gun. I've made a couple pipe fitting shotguns already. Pretty fun. One has a pistol grip and the other is fitted into a stock.

 

[ugaarguy]

Yep, just go 18"+ on the bbl and 26"+ overall length. For a few years Marlin even made the 25MG Garden Gun, which was classified as a shotgun. It was literally a smooth bore version of their model 25 .22 WMR bolt action rifle.

 

[Nickel Plated]

Smooth bore long gun? Sounds like ashotgun to me. The ATF doesn't much care what cartridge you actually fire out of the thing. If it's smooth-bore, 18" barrel, 26" OAL and has a stock it's a shotgun.
Since you're building it from scratch, you can actually give it a <18" barrel as long as OAL is over 26" and it never has a stock. And it's a smoothbore.

To be honest though, a smoothbore barrel. Especially one made through expedient means will give you an almost useless level of accuracy.
I suggest designing the gun so it CAN be made with just a smooth tube for a barrel if you really want it to be an expedient SHTF design. But for the actual working prototype just use a rifled barrel blank and make a proper barrel with the same mounting design as the tube barrel. That way you can atleast use the thing as a decent range toy if you wish.