My buddy for several years did make bulk purchases but not like your may think.
He would buy a case or two in a years time and over said time or longer sale off those that did not meet his collection standards.
noelf2 nailed it I think
(C) as applied to a dealer in firearms, as defined in section 921 (a)(11)(A), a person who devotes time, attention, and labor to dealing in firearms as a regular course of trade or business with the principal objective of livelihood and profit through the repetitive purchase and resale of firearms, but such term shall not include a person who makes occasional sales, exchanges, or purchases of firearms for the enhancement of a personal collection or for a hobby, or who sells all or part of his personal collection of firearms;
It was clearly a hobby and not a full time gig.