I actually did see a WWII era flame-thrower at a Dallas gun show, in the downtown convention center, once. But it was a Class III item, I bet.
I've seen people in South Texas make flamethrowers to set brush piles on fire.
When they clear the mesquite with a dozer each brush piles will be over a mile long sometimes. There might be 30 to 40 piles.
They will take a flamethrower and just drive along the pile hitting it every now and then the light it up. I wouldn't want to be on the receiving end of one of those things, but really cool looking from the back side.
Why should it be Class III?
It’s certainly not full-auto and the range is severely limited.
Nope. Not Class III, not regulated at all, unless you spray weed killer with it.
I had one, sold it to a fella that rents them out at target shooting events and military reenactments at $150 a pop. He paid for the one he got from me with his first ten rentals.