I actually worked as a millwright in a family business for eight years before I went to work for a fire department. So I already have the skill set and tools available to finish an 80% receiver and get good results. I still would probably purchase a kit with jigs and instructions to save time and effort. So of course the “Ghost Gunner” CNC Mill is certainly not necessary to finish an 80% AR receiver but it is an amazing effort and was designed as much to tweak the noses of liberal politicians as it was to finish 80% AR Lowers. It comes from the same guy, Cody Wilson who designed the most well known 3-D printed gun, the Liberator 3D-printable pistol. They have actually already sold hundreds of “Ghost Gunner” CNC Mills and it is totally freaking out liberal politicians.
Is it worth the money? The CNC mill is a time saver and may help get more consistent results depending on your skill level. The coding and set up is the time consuming part that takes knowledge and skills that most people do not have if they were trying to do something like this completely on their own. The entire Ghost Gunner project is “open source” people outside of Defense Distributed have been assisting in the development of both the tooling, jigs and the coding.
Make a deposit on one of these if you want to assist Cody Wilson and Co. with his agenda and legal battles with the government. I personally would consider one of the primary objectives to be helping in an effort that is completely and effectively freaking out the media and the left and living in their heads. The gun controllers would be banning drill presses if they thought it would help keep "homemade" ARs out of our gun loving hands.
As word has gotten out and these things have been perfected the price has gone from $1000 to $1500 and I understand that they have a huge backlog of orders. I have no idea what the wait time is; I am sure that it is measured in multiple months or more. If their ongoing legal battles go bad you might even lose your $250 deposit... so it isn't an option for me. But what a conversation piece if you actually ended up with one!
“So how strong does an AR15 style lower receiver have to be. Couldn’t it be made of plastic or even wood, so long as the holes all line up?” [captain_dave, post 21]
“People have printed lowers out of plastic with 3D printers but they are for demonstration purposes and not considered strong or durable enough for actual use with standard cartridges.” [fireman15, post 25]
“... the most well known 3-D printed gun, the Liberator 3D-printable pistol....” [fireman15, post 65]
The notion that 3D printing will fully supplant more traditional materials and methods in gun manufacture is nonsensical.
Wood is unsuitable for lower receivers: not stiff enough, not stable enough in a dimensional sense.
Polymer suffers from the same limitations that rule out wood, but (in proper formulations only) has become viable thanks to innovative design, and incorporation of composite materials and stiffening inserts. Makers of successful polymer-frame arms guard their plastic formulation jealously; the prospective 3D-print home workshop gun builder is not going succeed by substituting bulk plastic pellets from Hobby Lobby.
Plain unalloyed aluminum is not used in gun parts manufacture - doesn’t wear very well. If one can obtain suitable alloy, it still isn’t a simple matter of proper accuracy and precision in machining. The major aluminum parts of AR-15-style arms are in part forged, not machined from blanks. And following forging and machining, they are selectively heat-treated.
3D printing cannot overcome any of these limitations. But there are greater constraints 3D printing will never overcome: working parts like barrels, bolts, firing pins, hammers, sears, triggers must be carburized (case-hardened) or heat-treated and tempered. Unhardened, untempered parts may work in theory, but at best will deliver only a few shots before wearing out of spec. And steel is the only metal strong enough to stand the pressures of militarily effective cartridges. Forum members valuing their own safety - and that of loved ones - are urged to avoid 3D-printed guns purporting to handle such.
Springs are the toughest limitation of all: they can be fashioned of only a limited number of materials, and they must be tempered after forming. No 3D printing process will ever create a spring.
Gunmakers are not blind to the advantages of built-up parts (of which 3D printing is only the most recent iteration), but they have labored for generations to improve the techniques needed (sintering and MIM are two); many gun owners have had problems with parts made thus, and are not at all willing to agree that they are suitable replacements for more traditional methods.
Even if theoretically perfect, suitably precise parts of adequate temper and hardness could be fashioned by some hitherto-undiscovered variation of 3D printing or other buildup technique, they cannot be just slapped together to become a functioning gun. Hand fitting and adjustment are always required: safe and functional tolerance ranges are simply too small.
The self-absorbed revolutionaries who are so convinced digital changes everything need to stick to what they know.