If the firearm is legally registered as a pistol then the method to convert it to an SBR is incredibly simple.
Q: Do I have to engrave the firearm?
A: No..and yes. If you plan to keep the weapon for yourself and have no intention of selling it then you do not need to engrave it. While it is considered re-manufactured the current serial number is all the ATF needs as long as it is in your possession. If you plan to sell the firearm later then you will need to have it engraved with the appropriate info beforehand. This is covered in the ATF FAQ section. 除非我以后有打算卖掉这枪才需要engrave,这个是正确的吗? 我是没有打算转手的