On the Annual Firearms Manufacturers and Export Report (AFMER) form, Instruction 2 (a) defines "production" as firearms manufactured during the calendar year, to include separate frames or receivers, actions or barreled actions, disposed of in commerce.
A manufacturer who acquires these items from another licensed manufacturer in the assembly and production of complete firearms will include the manufacture of these firearms in their own report. Separate frames or receivers, actions, or barreled actions are to be included in this report when they are exported or disposed of in commerce to a person other than a licensed manufacturer.
If you manufacture and sell a firearm to a non-manufacturer, you are to report it in the year you sell it.
If you manufacture firearms and send them to another licensed manufacturer to finish assembly, and the other manufacturer sells the firearms into commerce or exports them, then you do NOT include these firearms on your report.
If you manufacture a firearms part, send it to another licensed manufacturer for further assembly, and the other manufacturer returns it to you and you then sell it into U.S. commerce or export it outside the U.S., then you do include the firearm(s) on your report, in the year they entered commerce or were exported.