First, I spoke in error with regards to the use of the Button Broach. The ID of the barrell is Gun Drilled first, and sometimes Gun-Reamed to produce the ID hole. The Carbide "Button" Broach then is either pushed or pulled to produce the rifling at th desired helix angle as well as depth, etc. The "Button" broach does not creat chips like a standard keyway broach would do, it "Swedges" or "moves" the metal thur plastic deformation-a lot like the process a "Thread Forming" tap would do compared to a cutting tap. I hope this is a better answer.
Also-Kurt, FYI-Pacific Tool and JGS cannot help me, however Apex Broach, Danjon Co, or Drill MAster can.