Originally Posted by
MistWolf
If you have not yet configured the lowers as rifles, you may configure them as pistols. From my research, the BATF states a lower isn't a pistol or rifle until it is barreled. A lower with a rifle stock (no upper) is still transferred as "OTHER" because the stock can be removed to be configured as a pistol.
If you first configure a receiver as a rifle, it will always be a rifle.
If you first configure a receiver as a pistol, you may reconfigure it as a rifle. A pistol receiver that is re-configured as a rifle may again be re-configured as a pistol. It is up to the possessor to perform the re-configuration in a sequence so that it is never in an illegal configuration.
These rulings are the result of the lawsuit by Thompson Center vs the BATF.
Unless the first configuration of your lowers were as a rifle and a rifle barrel installed, it may still be configured as a pistol