Quick notes - you can’t print everything you need to make a firearm, or, more correctly, you can’t print everything you need to make a firearm that works more than once. In the case of the ubiquitous Glock, you’re printing the frame, which is the serialized part, and therefore the entire ‘gun’ under US law. Once you have that, you can buy all the other parts with cash and no ID check (in most states). Without very, very expensive metal-printing technology, you can’t print, e.g., a barrel, or a slide.
Second, resin printing is extremely precise. Some resin printers are +/- .0001"; that’s more than accurate enough for firearms. That said, resin prints aren’t durable enough to be used for guns; you would want something glass-reinforced for a Glock frame, or an AR-15 lower receiver.
Prices for printing are far, far lower than CNC costs. The smallest metal-cutting CNC mill that I’m aware of starts at about $60,000, and that’s for the bare machine. Tooling is going to cost several times that. If you’re a professional gunsmith, it might make sense to buy one, if you do a lot of slide milling (for optics, or cuts to reduce the weight), or if you’re making a lot of custom muzzle brakes, but gunsmithing doesn’t tend to be a very lucrative career.
Quick notes - you can’t print everything you need to make a firearm, or, more correctly, you can’t print everything you need to make a firearm that works more than once. In the case of the ubiquitous Glock, you’re printing the frame, which is the serialized part, and therefore the entire ‘gun’ under US law. Once you have that, you can buy all the other parts with cash and no ID check (in most states). Without very, very expensive metal-printing technology, you can’t print, e.g., a barrel, or a slide.
Second, resin printing is extremely precise. Some resin printers are +/- .0001"; that’s more than accurate enough for firearms. That said, resin prints aren’t durable enough to be used for guns; you would want something glass-reinforced for a Glock frame, or an AR-15 lower receiver.
Prices for printing are far, far lower than CNC costs. The smallest metal-cutting CNC mill that I’m aware of starts at about $60,000, and that’s for the bare machine. Tooling is going to cost several times that. If you’re a professional gunsmith, it might make sense to buy one, if you do a lot of slide milling (for optics, or cuts to reduce the weight), or if you’re making a lot of custom muzzle brakes, but gunsmithing doesn’t tend to be a very lucrative career.