Sorry friends, Looks like curiosity helps me procrastinate from studying for exams...

1. I purchase a pre-86 RDIAS & fire control parts.

2. I purchase a LEO lower stamped "Safe-Fire-Auto/Burst" from an officer.

3. I maintain all post ban compliances i.e. crowned barrel, no lug, trapdoor stock.

Is this doable?

If you do the standard paper (CLEO sign-off, approved Form 4) this will be okay. Otherwise, no. The DIASs listed for sale in SHotgun news are NOT legal to actually put in an AR series weapon, or even possess if you own an AR-type weapon. Only DIASs that are registered as machineguns pursuant to the National Firearms Act may be legally used to convert a weapon to full auto.



Probably not. A LEO only Assault Weapon lower [b]MAY[/b] be legal, if enough AW features are removed from the weapon, and the lower is not one specifically listed in the ban (AR-15). However, if the lower was originally manufactured as an MG, and that is why it is marked with FA markings, then that lower is a registered MG, registered on a Form 10 to a PD or dealer, most likely, and is likely stolen, so you would be facing two or three felonies for buying it. If it was just marked for cosmetic reasons after manufacture, you might be okay. Given the possible penalties, it would be far, far cheaper to just use a cheap postban lower for your host gun for the legal DIAS (see below). I would stay very, very far away from this lower.



That doesn't matter is the overall weapon is a legal machinegun. A machinegun is not a rifle or a shotgun for the purposes of the 94 AW ban, so if you have a legal, registered DIAS, the host weapon for the DIAS can have all of the evil features you want.

Actually, the 94 AW ban doesn't apply because the weapon is no longer 'semi auto', not because it's no longer a rifle or shotgun (which it still is).  An M16 is both a rifle and a machinegun.  A full auto striker 12 would be both a shotgun and a machinegun.