Ten years in, it sure feels like it. Regret it daily.
Fastest way to destroy a fantastic hobby.
If we're just talking "built" as in assembled; not actually manufacturing... and we open that up to semi autos...
At the peak of Modern Sporters, I was putting MS18-A3's together at around 14 rifles an hour. Those were the days....
I shouldn't have been so snide, my apologies.
That's why I never went into the business.
I worked for Alan Lever, starting in my teens. My first job was sweeping up the floors, etc, shortly afterwards, Alan asked me if I wanted to learn a bit about the different firearms he was bringing in for distribution to other stores and customers.
The vast majority of it was surplus firearms, from SMGs, to semi auto rifles, bolt actions, LMGs and HMGs, dozens of different types of handguns and a few cannons, both muzzle and breech loading types. I got to live in the warehouse as part of my pay. I was in heaven and it smelled like grease and varsol.
It took a while for me to figure out that he couldn't get anyone else to do the job, but there were great benefits, such as my pick of the surplus firearms for $1/pound for NIW/EXC or less, depending on condition.
I had to disassemble, keep all of the parts for each firearm separate, clean, assemble, then inspect for function, sometimes test fire, so I got the best of the best available.
Even went on a couple of buying trips with him. Nice guy, after he dropped the "crusty old boy" personae.
I opened a small fly tying supply business, no rods and such but materials for tying the flies. Couldn't make a dime on hooks, so started producing my own dubbing blends. It was profitable but nothing to make a living from, even though I supplied over twenty shops.
The smithing I do now and the builds are for my own pleasure, other than to keep a few select folks going with their older firearms, which they would never take to a smith if they had to pay cash they don't have. It keeps them in the hunting game for now anyway.
Good luck to you, it's a hard business, even when times are good for firearms enthusiasts.