Is it legal?

[JusticeM4]

Most cops know NOTHING about the NFA and may or may not place a call to an ATF agent to ask a question that they get to word such as,"I got this guy with what looks like an SBR, he says he can't put a stock on it but it sure looks like he can. He says a stock won't fit but it has the stock position holes, what should I do?" Two possible answers: seize the weapon and we will figure it out; or, seize the weapon and arrest the owner and we will figure it out. So, carry the letter that comes with a brace if you use one, and use a pistol buffer extension if you are building a pistol. Even a legitimate defense will probably require legal expenses.

We can argue hypothetical what-if scenarios ad naseaum. There is not just 2 answers to a particular scenario--there are many. And if the cop called the ATF, the agent should provide the answer anyway if the firearm is legal or not (solves that issue).

It is already been stated multiple times that using a standard RE/buffer tube on an AR pistol lower is legal.

[SilentRecon]

We can argue hypothetical what-if scenarios ad naseaum. There is not just 2 answers to a particular scenario--there are many. And if the cop called the ATF, the agent should provide the answer anyway if the firearm is legal or not (solves that issue).

It is already been stated multiple times that using a standard RE/buffer tube on an AR pistol lower is legal.