AR pistol buffer tube length question

[bikemutt]

I want to try a longer buffer tube on a 9mm AR pistol, specifically I want to try a tube designed for an A1/A2 rifle stock. It seems to me that could be interpreted as constructing an unregistered SBR, especially if I happened to have an A2 stock in my possession.

Would it be legal to do this if I were to permanently remove, or plug, the threaded lug at the butt end of the tube so there would be no way to properly affix an A2 stock?

 

[Theohazard]

Yes.

If you don't modify the buffer tube, then there's the small possibility that you could be charged with constructive possession if you had a stock in "close proximity" with "no other useful purpose". But if you permanently modify the buffer tube so it can't accept a stock, that issue goes away and you have nothing to worry about.

 

[pjeski]

True you have to be careful to avoid constructive possession. But there is no requirement to use a pistol tube or even to modify it. If you have another practical use for the stock, you're probably ok. But modifying it is a good idea. There is a letter out there on this.