'Nuther way of saying it is; "inventing something fool proof, they just invent better fools"
It's entirely possible to blow the cap off by pushing harder on the handle trying to size a 7-08 neck tight enough so I couldn't seat a bullet deeper by pushing against the bench. The Bonanza co-ax has plenty of compound leverage to do it! Yes the alum cap is a safety valve. I ended up chucking the mandrel in a hole shooter, working about .0015 off of it, to make the necks internally smaller to grip the bullets better.