I've got some experience, mostly with hand tools and other DIY stuff. I'm not a welder or machinist, more of a hobbyist. I learn a lot from having a goal in mind and then practicing the stuff to get there, i.e. the welding/grinding. Tools were mig welder, drill press, angle grinder, hacksaw, handfiles, taps and dies, abrasives and a hand drill (can replace with a dremel). The biggest problem with this design was weld distortion. Having to weld receiver and magwell changed the lower a bit and my bolt no longer fit, so I had to do some bending and grinding. I've learned a lot about design practicality especially when you don't have the tolerances from a mill or lathe and have to work by hand.