Is a roll crimp really necessary on a 9mm Mak? I've already reloaded about 300 rounds through a 3 die setup without a roll crimp & shot most of them with no problems going into battery. Then, after comparing some factory rounds which had the roll crimp, should I just leave well-enough alone?
straight walled pistol cases dont need roll crimps unless the bullet your loading has a cannelure. just use a taper crimp die to straighten the bell from the expander back into spec.
roll crimping a non-cannelure bullet will actually loosen the bullet in the case and cause fail to fire or go into battery as rimless straight wall cases headspace off the case mouth.
lee factory crimp dies are supposed to indent a noncannelure bullet and give it a factory style crimp. im not convinced its a needed or desired thing on non-cannelure bullets.
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent