The BATF has advised people to be on the lookout for fraudulent National Firearms Act (NFA) tax registration forms being used to sell NFA firearms (machine guns and the like).

The scam involves use of the fake Form 4 to obtain a deposit but the firearm is never delivered, according to ATF.
According to an ATF bulletin:

“A typical scam starts with a perpetrator (seller) claiming ownership of an NFA firearm through an altered Form 4, and then contacting an FFL to see if that FFL is interested in purchasing the NFA firearm. If the FFL expresses interest, the seller then requests that the FFL pay a percentage of the money upfront via cashier’s check and the remainder of the money after the ATF Form 4 paperwork is finalized. All communication is done via email. If the fraudulent documents are printed, they appear to be rough scans of an original approved ATF Form 4. However, if the documents are viewed on a computer screen and are magnified, it often becomes evident that various sections have been altered.”