Most manufacturers guard their manufacturing processes about the way
KFC guards Colonel Sanders’s 11 Herbs and Spices Coca-Cola guards the Coke recipe. They would no more show you a video of lower receiver machining than they would give you the product. Indeed, some mnufacturers not only won’t let us tour their plants, they won’t give us still photos, talk about processes, or even let their own workers bring smartphones or cameras in certain areas.
A time- and money-saving way to do a standard process can be that big of a competitive advantage.
But here’s midsize manufacturer Palmetto State Defense using a 5-axis machine to take AR-15 lower receiver forgings to 80%.
To us, it was interesting to watch how they rough milled the magazine well to approximate shape, and then CNC broached it to final shape (the rasp of the broach is unmistakeable). The end mill removes lots of metal fast, but the broach gets net shape and surface finish up to standard.
Note how much coolant/cutting fluid is used on these operations!
The link at the YouTube page no longer takes you to a buy page; PSD no longer sells the 80% lowers, apparently. They do make some attractive finished rifles, and one thing they’re selling is 200 rifles that were, supposedly, used in the Range 15 movie. (At press time, they still have 92 5.56 and 95 .300 Blackout rifles in stock). See ’em here.