Has anyone completed an 80% pistol frame by Polymer80? Do you register it after you complete it? Thanks in advance.

Has anyone completed an 80% pistol frame by Polymer80? Do you register it after you complete it? Thanks in advance.

Maybe the better question is "WHEN do you register it?."

Once the frame is more than 80% complete, it is a firearm.  At that point, you are required to register.

You have 5 days from that point to register according to the law.  Most people can complete the job in one day, or at least in one weekend.  There should not be a problem registering the receiver at 100% complete within 5 days.

There's no reason you can't register when the receiver is less than 100% complete.  Having said that, there's no way for anyone to know when you started milling nor when you finished.  Therefore, it will have taken you no more than 2 days to finish milling no matter how many days you worked on it. 

And it will have been completed yesterday no matter what.

Volunteering more information than that is imprudent.   

Not strictly true, In Hawaii "Firearm" means any weapon, for which the operating force is an explosive, including but not limited to pistols, revolvers, rifles, shotguns, automatic firearms, noxious gas projectors, mortars, bombs, and cannon.

As such a 99.99% lower is not a firearm, as upuntill completion it can not function with explosive force.

One could go further and say that an finished lower is not a firearm IF the creator states that it is not a weapon and is in fact for target shooting only and as such would not require registration at all.

If you take the registration at 80.01% as a requirement, then you would also need to make sure that you have the correct permits before manufacturing.

The GCA defines the term “firearm” as:

(A) any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile
by the action of an explosive;
(B) the frame or receiver of any such weapon;
(C) any firearm muffler or firearm silencer; or
(D) any destructive device.

Such term does not include an antique firearm.

Under 18 U.S.C. 921 (a)(21)(A), the term “engaged in the business” means— as applied to a manufacturer of firearms,
a person who devotes time, attention, and labor to manufacturing firearms as a regular course of trade or business with
the principal objective of livelihood and profit through the sale or distribution of the firearms manufactured.

Both the permit to acquire and registration sections of HRS 134 state "whether usable or unusable, serviceable or unserviceable".  Your argument pertaining to "function" is invalid.

What the "creator" states its purpose is is irrelevant.  If it meets the criteria for a firearm, it's a firearm.

The ATF doesn't recognize milling an 80% receiver as "manufacturing."