I have a stamp for my SBR, so my form 1 passed initial muster.
My question is this: Would I be illegal if I put a 12" 300 Blackout upper on a receiver that had 5.56 and 10 inches listed in Block 4?
I need to see something substantive beyond opinions, but have been unable to find anything.
Help anyone?
It is my understanding that you can put whatever upper you want on it, as long as you can return it to the listed configuration.
*not a lawyer
There’s no requirement to be able to return it to the specs on the form.
The specs you provided are for the initial making of a firearm. That’s a one-time act, with a specific caliber and length. Once that’s done, you can configure it as you wish.
And you won’t. It is still an SBR when you change it.