Pistol or SBR

[Quiet]

I thought that only adding a stock would make it an SBR. Where do you see a foregrip requiring an special tax stamp?

You are correct in that adding a shoulder stock to a handgun would make it a SBR.

Adding a vertical forward grip to a handgun makes it an AOW and a tax stamp is required.

Adding a horizontal or angled foregrip to a handgun does not make it a Title 2 firearm and no tax stamp is required.