Could refer to a specific step in the "train stop" navigation of the eForm 4 system or the requirement for a digital photograph.
Specifically referring to the "Application to Transfer and Register NFA Firearm". EFAFPmp4
A specialized version of the standard MP4 file format used for efficient internet streaming and faster processing of video data. Deep Dive into Fragmented MP4 (fMP4) Could refer to a specific step in the
Commonly used by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) for their online submission system. EFAFPmp4