I played that game for a few years.
@Sunray obviously has never carried his Type 6, else he wouldn't be making up gibberish about a dozen licenses and permits to be carried. Other than the FFL, it's no different than operating any other business, in terms of licenses. The liability insurance is expensive, and the ITAR requirements can be a headache.
I'll also comment, there are a lot more guys who shoot these high dollar weatherby and DG type rounds who do NOT reload than a person would organically think. That was a big part of how I justified my business when I carried my Type 6. It's just a matter of finding the right customer base - because a lot of those folks will buy a rifle, make a trip across the pond, and then resell it afterwards. Not a bad cradle-to-grave business opportunity if you can manage some inventory cost, get your Type 1 and 6, member up with DSC & SCI local chapters, have rifles for sale and load the ammo to go with them. Heck, "rent" the rifle for the trips if you so desired. It's incredibly difficult to hold any profit margin on bulk ammo for blasters - but ONE way around that is to load for competitive shooters. They need high volume ammo, but they also need specialty loads/dimensions, AND they'd rather spend their time practicing instead of loading (and you should market your services as such!!), so there IS a market there. Hook into local CAS/SASS, IDPA/IPSC, 3gun, etc clubs.
I've loaded for a lot of people over the years, ranging from no-money-exchanged to letting folks use my gear to selling for profit under a Type 6. I use a holding company to "own" the equipment, then an LLC for the operations. I do carry liability insurance, I wanna say something on the order of $2m, would have to check my policy to be sure - I know I carry less than my father who O/O a industrial/commercial facility pest control company, where he has employees in company owned vehicles running hazmat up and down the road, and applying even in medical institutions and pharmaceutical production facilities, and my insurance premium is lower than his. There's a release of liability (nothing covers negligence, so cover your production method appropriately to refute negligence) I've used with customers - recognizing the inherent danger of the products and of sporting firearms use. I had 2 turrets and 3 progressives set up, and I can't recall how many different turret heads - I had drawers on drawers of tackle boxes with dummy rounds for different customers Custom dimension ammo.
If you're able to find a large enough volume of obsolete or wildcat cartridge customers, you can justify your own headstamps and your own production runs of these brass, OR you can justify doing your own brass forming work (hydroforming dies can let you "fireform" to produce rounds which require it). There are companies out there selling custom produced or custom formed obsolete cartridge brass, it's a niche market, but if you can access it, you might be able to stay competitive since you're not looking for typical margins.