Now if you as an individual have a regular day job, and you only engage in the firearms business on the side once every month or less, then it is NOT your primary means of livelihood and only a supplement to your income.
You missed it all entirely didn't you?
What other jobs you may have has no bearing.
The operative concepts are
(1) devoting time, attention and labor; (once a month or less is still fits)
(2) doing so regularly as a trade or business; (This still fits)
(3) the repetitive purchase and resale of guns; and (Yes, still fits)
(4) intending to make money.(Definitely fits).
What kills your entire statement is this
"and you only engage in the firearms business"
The word business is the operative word that sinks it. You can't do this with the objective being to make money, even a little bit, even if you actually lose money. As long as the objective, the point, your effort, is to make money, then you are guilty.