If you understand the firearms business and understand gun laws the whole thing is absurd.
First the most restrictive laws and regulations are unique to each state.
Second there is no way you could be involved in dealing any quantity of guns without a federal license.
As for the manufacturing part if you decide to be an unlicensed manufacturer the BATF will be on your ass like flies on sugar, specially if you are building machine guns , silencers or other highly regulated items.