Building a SBR with the ATF Form 1: Do you Need to Engrave your Caliber if Denoted as Multical?
by National Gun Trusts
If you are manufacturing or making a SBR with the ATF Form 1, you might have to engrave the caliber of your SBR on the lower receiver. This is an addition to having to engrave the information of the information from the individual, trust or legal entity that applied for the ATF Form 1 or the ATF eForm 1 tax stamp. You can view the walk-through guide to determine what you need to engrave on your SBR as applicant here - ATF NFA Engraving Requirements Walk-Through Guide. The following lower receiver engraving information is only required for lower receivers that are already engraved as "MULTICAL", "CAL MULTI", "MULTI CAL", "CAL.MULTI", or other derivations that indicates that the caliber is not definite and maybe able to operate with multiple calibers. In addition to having to engrave the applicants information on the lower receiver of the SBR, you will also need to engrave the caliber of the SBR configuration that you are applying for. The ATF doesn't allow for the designation of "MULTICAL", "CAL MULTI", "MULTI CAL", "CAL.MULTI", or other derivations. They require one caliber. This means that when you are applying with your ATF Form 1 or the ATF eForm 1 you will need to designate the caliber that you want to use with your SBR, e.g if you state on your application that your SBR is 9mm, then you will need to engrave the applicants information and the caliber 9mm. Engraving and applying for the ATF Form 1 and the ATF eForm 1 tax stamp application with the caliber designated as 9mm doesn't mean that you cannot change the upper receiver at a later time to use a different caliber then your ATF tax stamp. In order to do so you can send a letter to the ATF noting this and your ATF tax stamp will be amended with the new upper caliber. You can view our article about this here - Changing Your SBR Upper with a Different Caliber Than the Registered Lower