Is the restriction on making bullets for sale the same as making guns? Seems like a very lucrative business. Don't bullets also "expire" after a certain period of time?
For domestic production, it's basically just a different ATF permit. The reason why there's so many shortages is because the cost of setting up a new production line is a huge upfront cost, and if the demand for ammo goes down (which it historically has after spikes) then that will have been a wasted investment. It's actually the same problem happening right now with graphics cards.
>Don't bullets also "expire" after a certain period of time?
Only on a timescale of decades, and even then it's more a matter of reliability because of corrosion and the like. Most WWII surplus ammo should still fire perfectly fine.
Modern powder and primers (and thus an assembled ammunition cartridge) easily last decades, almost indefinitely if stored well.
There are effectively no primers for sale right now for common calibers, and that’s been the case since ~February of 2020.
Oh, and it’s not “black powder”, but “smokeless powder”. There are tons of varieties, and most are only suitable for one or two applications. Pistol powder is different from rifle powder, for example.
Usually it’s not a big deal if the person using the firearm knows what to look out for.
But with factory made ammo the chances of even a slight misfire vs reloading are drastically lower.
I would only buy reloaded ammo from someone I personally trusted or if I did it myself (not that I know how, but I’d trust me learning it over someone trying to make some money on the margin between factory and reloaded ammo)
In old ammunition, the primary concerns are the corrosive residue the ammunition will leave behind, rounds that won't go off at all, or rounds with a delayed reaction ("hangfire".) Hangfires can be dangerous if they go unnoticed, but aren't spontaneous "gun explodes in your face" events. You're also fairly likely to experience hangfires and rounds that simply don't work when shooting new production cheap 22lr; rimfire is notoriously unreliable and when rimfire ammunition is made cheap, you'll encounter 'duds' often enough. If you're at a gun range just trying to have fun, this is generally little more than an annoyance.
Centerfire ammunition is more reliable in general. With ancient centerfire ammunition, you have to wonder whether the ammunition was ever any good in the first place. A century ago, there were plenty of companies/countries making really shitty rifle ammunition that you might still find for sale today. That ammunition was never good at the time, and age hasn't made it any better. But some companies/countries were also making perfectly good ammunition a century ago, and that ammunition is generally just as reliable today as it ever was. But it will leave behind hydrophilic corrosive salts in your gun, so maybe think twice before shooting lots of it then neglecting to clean your gun.