The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) promised to stop violating Americans’ Second Amendment rights. However, a recent determination letter issued by the Firearms and Ammunition Technology Division (FATD), Firearms Technology Industry Service Branch (FTISB) shows that some anti-gun examiners still exist within the Bureau.
The letter in question, supplied by Gun Owners of America (GOA), concerns an unfinished fire control unit (FCU) based on the Sig Sauer P365 design. After former President Joe Biden took office, he ordered the ATF to reclassify unfinished firearms frames and receivers as firearms. Unfinished frames and receivers are commonly referred to as “80% frames and receivers” in the firearms world. The Biden administration and other anti-gun activists and politicians called these items “ghost guns.” The ATF labels these items as “privately manufactured firearms” or “PMFs.” The ATF would respond to Biden’s call by reclassifying plastic 80% firearm frames as fully built guns, reversing years of previous determination letters.
The ATF stated that it changed its opinion due to the ease with which a plastic, unfinished frame can be converted into a functioning firearm. The government emphasized that the material was easy to work with. At the same time, it stated that metal receivers and flats that were not finished were not considered guns because of the difficulty of working with metal. This opinion included unfinished 1911 handgun frames. That led one person to submit an unfinished sample of a P365-style FCU to the ATF to get a determination. In the Sig Sauer P365, the FCU is the serialized part of the gun. The FCU is made entirely of metal, so it would be reasonable for the submitter to assume that the ATF would approve the item.
The ATF rejected the sample, stating that the device is a “firearm” under the Gun Control Act of 1968 (GCA).
FTISB stated that its examiners believe the unfinished FCU has reached a stage where it can be readily convertible. To complete the FCU, a person would need to use specific drill bits and a drill press, among other tools. The Polymer80 plastic frame was determined to be a firearm because it could be finished with a simple hand drill and an Exacto knife. The FCU in question needs more finishing than an 80% AR-15, which the ATF doesn’t consider to be a firearm.
BREAKING
A GOA member has received an anti-gun determination letter from ATF.
ATF determined that an unfinished part is legally a “firearm”—even though @ATFHQ admits it has no idea how to complete it into a functioning weapon. pic.twitter.com/VGwVesQUk7
— Gun Owners of America (@GunOwners) September 3, 2025
The letter reads: “The FTISB has determined that the submitted sample has reached a stage of manufacturing where it ‘may readily be completed, assembled, restored, or otherwise converted to function as a frame or receiver…’ See 27 C.F.R § 478.12 (c). Therefore, the submitted P365 ‘partially complete’ frame is a ‘firearm’ as defined in the GCA, 18 U.S.C § 921(a)(3). Please note this classification only applies to the sample itself, precisely as submitted.”
The letter issued by the ATF shows that not all the anti-gun employees have been purged from the embattled Bureau. Since the P365 frame is more complicated to finish than an 80% AR-15 receiver, it seems like the FTISB is expanding the rule.
This decision appears to be in direct opposition to President Donald Trump’s Executive Order on the Second Amendment, in which he instructed the Department of Justice (DOJ), the parent agency of the ATF, to cease infringing on Americans’ natural right to keep and bear arms. It remains possible that a rogue employee at the Bureau made the decision unilaterally, or that it is part of a more widespread issue within FTISB.
After Trump took office, the FTISB vowed to be more of a partner to the industry than an adversary, but this letter raises questions about whether the ATF was serious or merely paying lip service.
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About John Crump
Mr. Crump is an NRA instructor and a constitutional activist. John has written about firearms, interviewed people from all walks of life, and on the Constitution. John lives in Northern Virginia with his wife and sons, follow him on X at @crumpyss, or at www.crumpy.com.