Firearms FNH PS90 SBR

That being the functional issues.
The paperwork/legal issues are that you have a registered SBR. You can’t just change the barrel to “de-register” the rifle as an SBR. The paperwork must be proper before it can change hands.
I recommend you either call the ATF NFA branch or reach out to knowledgeable SOT to advise you on how to proceed.
GLWS
 
That being the functional issues.
The paperwork/legal issues are that you have a registered SBR. You can’t just change the barrel to “de-register” the rifle as an SBR. The paperwork must be proper before it can change hands.
I recommend you either call the ATF NFA branch or reach out to knowledgeable SOT to advise you on how to proceed.
GLWS
Yes. I wasnt recommending that removing the barrel removed it from the registry. This will require a call and a letter to the ATF. Done this a few times on ARs, but those are much easier to disassemble. I wasn't aware of the difficulties to remove ps90 barrels