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Has anybody ever used the innovative technologies belted magnum sizing die? www.larrywillis.com
he claims this is the answer to the swelling in the case just above the belt.
[/ QUOTE ]Larry Willis states in his web site about full-length belted cases:
"The belt on a belted magnum case prevents any conventional resizing die from traveling far enough down the case. Then as the case is withdrawn, the brass also 'springs back' slightly."
I disagree with that. As the belt doesn't touch any part of a traditional belted case full-length sizing die, it's not the belt's fault. The die's got a relief area cut out of its base so the belt won't be touched. And part of that relief cut extends several thousandths of an inch in front of where the case belt is when the bottom of the die contacts the shell holder.
Here's what Fred Huntington (RCBS founder/owner) told me back in the early 1970's. Die makers don't dare make a belted case full-length sizing die that would size completely to the belt. As belted cases have the tightest headspace tolerances for both new cases and headspace gages, most folks wouldn't take the time to pay attention to the details of precice die position in the press. Too many people would set the die too far down and end up crushing the front edge of the belt causing headspace problems.
So it's not the belt on the case causing the problem. It's the way dies are made because most folks won't correctly set up a die that sizes a fired belted case all the way to the belt without damaging the belt and causing headspace problems. However, one can learn to set one of these collet type body dies correctly. It may take some time and careful inspecting along with some trial and error routines, but it can be done.
One of the greatest myths about belted cases is they were made that way to increase their strength at that point. Nothing could be further from the truth. Holland & Holland put that belt on some of their flanged (British term for rimmed) cases used only in double rifles so the same cartridge could also be used in a staggered box magazine bolt action rifle. Huge, rimmed cases don't feed reliably from such magazines. And the long, tapered shoulder on cases they used needed something at their back end to headspace on else the case would be driven too far forward in the chamber causing all sorts of extraction and head separation problems. That belt prevents the cartridge from catching the back end of one below it in the magazine and not letting the bolt push it forward into the chamber which happens with rimmed cases in staggered box magazines.