Thread: Roll Crimping
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Unread 01-22-2021, 08:07 PM   #19
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Originally Posted by Paul Harm View Post
Thanks, I found it. Their crimps are a whole lot deeper than mine. I think pressures may raise with a crimp that deep. I could be wrong - maybe someone else can chime in.
Whose crimps? The one shown on Reloaders is the same picture in all gauges (12). Depth from the rollover to the overshot card is entirely variable, and controllable. It's possible to get greater rollover depth with plastic hulls, than paper, but new Cheddite hulls are very pliable. Hull length, wad selection and shot charge all affect the height of the total charge. If you have a favorite wad, and the charge is well below the top of the case, you can select a different wad to bring it up, or trim the hulls, or, if it's only marginally lowere, use two or even three overshot cards.
The top of the shot only needs to be about 1/8" below the rim of the hull, and the rollover will be 180 degree reversed.
With regard to pressure, there's lots of data out there. All I have sent to Precision have been lower than folded samples of like charges.

The four shells, below, are, left-right:
Factory Eley 2.5" 5/8oz.
Once fired Winchester paper Super-X hull, trimmed to 2.4", Fiocchi RO28 wad, 5/8oz.
New Cheddite hull, trimmed to 2.5", Fiocchi RO28 wad, 3/4oz
New Cheddite hull, trimmed to 2.5", BPI SP28 wad, 5/8 oz

The difference between the Cheddite 5/8oz load, and Winchester Paper 5/8oz load is because the Paper hulls had very high base wad. The Winchester Hull with the SP28 wad only allows 9/16oz when trimmed the same.
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