Originally Posted by mountainman13
There's still the issue of what it is once your gun is attached to it. That may be considered a sbr and require proper licensing.
From Mechtech's FAQ section:
Is is legal to convert the CCU back to the original pistol?
Yes. The BATFE recently published a ruling which clarifies this - here is the link: http://www.atf.gov/regulations-rulings/rulings/atf-rulings/atf-ruling-2011-4.pdf
There has been a lot of missinformation circulating to the effect that once the pistol lower has been asembled to a rifle configuration then converting back to the pistol constitutes 'making a pistol from a rifle' and thereby placing the pistol into the SBR (short barrelled rifle) class. Not so. Please see our Forum for even further clarification. It is the first post on the Forum so you don't have to spend time trying to find it.