AR-15 Lower Made on CNC Machine

A friend of mine who has a CNC machine wants to try this. This kind of stuff is making me think I should start a category called “Gun Control Can Never Work”:

I’ve always wondered how well plastic would work for prototyping. There really isn’t a whole lot on the lower that takes huge stress, especially if you strap a .22LR upper to it for testing.

9 Responses to “AR-15 Lower Made on CNC Machine”

  1. Graumagus says:

    What they don’t realize is that a competent machinist can make one on a manual mill as well.

    Difficult, but far from impossible.

  2. grego says:

    it is easier than it looks to do the work… heck, even tiny benchtop mills can do the work if you tweak the design a bit.

  3. Laughingdog says:

    I’ve seen plastic lowers before. The problem is that plastic has a much larger coefficient of thermal expansion than metal does.

  4. Andrew S says:

    Hell, I wouldn’t even say difficult. Just time consuming. The only part of a gun that would be difficult for the home hobbyist to make is the barrel.

  5. PhilaBOR says:

    With a $2000 scanner you can scan in an existing lower, convert the point cloud to a CAD file, then use a CAM program to generate tool paths for your CNC mill.

  6. BTR says:

    The gov can’t stop criminals from doing things like making illegal weapons. They can just threaten good people with imprisonment into being unable to excersise their rights.

    We still have the absurb SBR and SBS restrictions on the books, when all it takes to violate them is a hunting gun and a hacksaw.

  7. David says:

    Anyone hear of plum crazy lowers? Cheap composite lowers.

  8. Graumagus says:

    The rifling is the only part of the barrel that’s even all that hard. You can get the steel from any number of suppliers and if you live in an area with any kind of industry you probably have at least one or two heat treating companies (I know of three within 10 miles of my home).

  9. E.S.Andrews says:

    Think about aluminum…

    Even aircraft-grade aluminum can be “machined” with accuracy and ease using home-built tooling and fixtures in a “milling machine” constructed out of a small bench-mounted drill press – if you’re only making one or a few parts, you can rough-cast aluminum in plaster-and-clay molds, then machine them using fixtures made with sheet metal, scrap angle iron and cabinet-grade particle-board/chipboard scrap. You can melt down the aluminum from any number of sources – old lawn mowers, junked barbecue grills, old auto transmission cases, etc. – and get more than enough raw material.

    Then there’s brass – and copper – and various thermoplastics like plexiglass and lexan…

    A small bench-mount lathe, like the ones available from Sears or Harbor Freight, can make barrels from ordinary steel bar stock – which can be bought from a scrap yard for very little money.

    If you have a garage, a basement, an attic – even an unused back bedroom – and the skills and some basic tools and machines and materials, there is effectively no such thing as “gun control/confiscation”…


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