[caver]

Call me ignorant, but I’m surprised that stripped receivers were not already considered a firearm.

[BobbyT]

They were. The point is that they’re being re-categorized from “long guns” (which is what they become when you build them, 18” long AR-15 “pistols” notwithstanding) to “other” where “other” doesn’t count as a long gun.

Thus preventing 20 year olds from buying them to do their own build vs. pre-made. 50 “common sense” steps down, another 50 “common sense” steps to go before we’re completely disarmed.

[gundog]

I’m surprised that stripped receivers were not already considered a firearm.

They are...hence the 4473.

[Still Thinking]

Call me ignorant, but I?m surprised that stripped receivers were not already considered a firearm.

OK, you're ignorant! Just kidding. They are and have always been considered "firearms". Their further classification has been in effect been changed from "not a handgun" to "not a rifle", meaning 18-20 year olds can no longer purchase them.