[dharmab]

It's simple.

~~The Assault Weapons Ban only applied to new guns.~~ ATF policy change, not AWB. Existing guns were grandfathered in.

Guns have many interchangeable parts. The part of the gun that the government considers to be the "legal definition" is a part called the lower receiver. You can change almost anything about a gun as long as you keep the lower receiver and comply with any other laws.

So if you buy an old MAC-10 lower receiver that was manufactured before the new ATF policy, and add an adapter [1] that allows it to be combined with the non-lower parts from an AR-15, you can create a completely legal Frankenrifle with mostly new parts!

This isn't even the craziest thing you can do with gun loopholes in the USA. "Pistol braces" [2], originally made for war veterans with amputations to shoot small rifles, have pretty much obsoleted restrictions on short-barreled rifles. "Ghost guns" [3], i.e. lower receivers that have no serial number and do not appear in any database, are easily made by anyone with access to CNC tools (including a few hours rental for a few hundred bucks). 3D printed pistols are becoming a thing [4], although they are not very durable.

1: https://aandsconversions.com/2018/11/25/the-next-big-thing-f...

2: https://www.sb-tactical.com/product-category/brace/

3: https://en.wikipedia.org/wiki/Ghost_gun

4: https://www.reddit.com/r/guns/comments/jzik44/magdump_monday...

[manfredo]

The automatic weapons ban (specifically the 1986 Machine Gun Act) is distinct from the Assault Weapons Ban. The Assault Weapons Ban was in the 1990s and banned the sale of semi-automatic guns with certain shapes of grip, bayonet lugs, and other features. It did not ban anything based on magazine capacity, as is often stated. It expired in the 2000s since it had a sunset provision that made it last 10 years if not renewed.

[WillPostForFood]

It did not ban anything based on magazine capacity, as is often stated.

You are right, it was mostly a ban based on superficial features like the much feared bayonet mount. But there were two bans based on magazine capacity.

It did ban magazines with more than 10 round capacity. It also banned semi-automatic shotguns with more than 5 round fixed magazine or a detachable magazine when in combination with folding stock or pistol grip.

[spamizbad]

Restrictions on SBRs never made sense anyway: it was a hold-over from the NFA back when they wanted to include pistols as well, but ultimately ripped that out of the legislation.