Thery are made on a bar fed cnc lathe. A bar feeder pushes stock through the headstock of the lathe. The tools do all of the work as it is held in a rotary collet, so all of the operations are done in one fixturing. There are bored, threaded, faced, contoured and milled before they are cut off. A secondary axis picks off the part and deburrs the tapered end.
So the business end is always square with the threads. You may notice on some that there are some minute burrs left from the slot milling operation on the face, but that can be remedied quick with a couple of swipes on a stone.