This machine is $200, and it’s faster to mill than 3d print. It won’t work for steel or aluminum, but a block of plastic would be just fine. So what is the advantage of printing a Glock frame vs milling one?

I just bought THIS ONE and while I have not tested the electronics yet, it came fast, well packaged, the plastic parts are all injection molded and well finished, and I think you'd be hard pressed to buy the extrusions, bearings, rails, and motors individually for the price. I am turning this one into a pen plotter but I may buy another to make a laser engraver.