SBR'd Lower With Any Upper

stanr5686

Joined: Mar 2021

Posts: 1

EE: 0% (0)

TX, USA

Posted: 3/15/2026 3:03:06 PM EDT

If I do the NFA Form 4 on a lower have it numbered and everything the ATF requires can I still run any upper that I want? Even if it's not an SBR. I have several lowers that I swap around uppers on. Does the SBR lock one of them up to only that?

D_Man

Well Lubricated

Joined: May 2008

Posts: 14401

EE: 100% (17)

OH, USA

Posted: 3/15/2026 3:09:59 PM EDT

[#1]

It would be a Form 1, not 4. But otherwise yes, you can use any upper you want on it. And it would only be legally regulated as an SBR when in an SBR configuration.

bluedog82

Member

Joined: Aug 2019

Posts: 5498

EE: 100% (42)

MI, USA

Posted: 3/15/2026 5:48:43 PM EDT

[#2]

FPNI.

TGWLDR

Joined: Dec 2014

Posts: 53973

EE: 100% (463)

USA

Posted: 3/15/2026 5:52:20 PM EDT

[#3]

https://www.ar15.com/forums/Armory/General-NFA-Questions/17/

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SBR'd Lower With Any Upper

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SBR'd Lower With Any Upper

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SBR'd Lower With Any Upper