Manufacturers pay $1000/yr to the ATF to be Special Occupation Taxpayers in addition to excise taxes on completed firearms (15% AFAIK). Wikipedia says if the SOT does less than $500K in business they get a $500 discount on their SOT tax.
https://en.wikipedia.org/wiki/Special_O ... _TaxpayersDealers pay $500/yr to be able to sell/transfer NFA items.
Individuals who "make" their own NFA weapons pay a $200 manufacturing tax. Individuals who transfer a NFA weapon pay a $200 transfer tax. Dealers, manufacturers, govt agencies and the heirs of deceased NFA owners who were listed as individuals on the Form4 (versus Corps/LLC/Trusts etc) are all tax free transfers.