It's just long enough to classify as a rifle under the NFA, so no $200 tax. It comes in only .308 winchester, though I think it can fire 7.62 NATO too (generally .308 wins can fire 7.62 NATO, but older 7.62 NATO guns maybe can't fire .308 win).

Also, all you need to change gas regulator options and disassemble the gun, and even to switch it from righty to lefty and back, is a round, or, if you don't want to waste a round (the bullet will get scored if you use it to turn the gas regulator control, and I wouldn't fire it out of an abundance of caution), a punch and any kind of key/allen key/screwdriver. It's amazing. And the pins are captive. Easy af to service.

EDIT: Oh, and it's a pleasure to answer your questions!

It's just long enough to classify as a rifle under the NFA, so no $200 tax. It comes in only .308 winchester, though I think it can fire 7.62 NATO too (generally .308 wins can fire 7.62 NATO, but older 7.62 NATO guns maybe can't fire .308 win).

Also, all you need to change gas regulator options and disassemble the gun, and even to switch it from righty to lefty and back, is a round, or, if you don't want to waste a round (the bullet will get scored if you use it to turn the gas regulator control, and I wouldn't fire it out of an abundance of caution), a punch and any kind of key/allen key/screwdriver. It's amazing. And the pins are captive. Easy af to service.