ZG47
AH fanatic
- Joined
- Jan 20, 2015
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- 899
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- Wellington, New Zealand
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- Hunted
- New Zealand
And hence the head spinning. You'd think there'd be a simple conversion formula since both are measuring pressure, but there isn't. So I simply don't even follow pressure tables very much. While the typical pressure signs (flattened primers, sticky bolts, extractor marks) are somewhat crude and from what I've read exhibit only well after "high" pressure has been exceeded, I use them along with my chronograph to tell me when I'm reaching a point where I need to back off.
The pressure tables are a nice reference point, but in my opinion they're only that and should not be taken as gospel truth one way or another as either safe or dangerous. Each and every load combination (brass, primer, powder - type and weight, bullet) is different for each rifle, or should be at least assumed so. What is too high a pressure in one rifle may be perfectly fine in another.
My understanding of the matter is that:
Where the piezo and c.u.p. (l.u.p. for low pressure rounds) expansion measurements are taken from the same point on the cartridge case, it is possible to extrapolate data;
BUT,
Where the measurements are taken from different points, which apparently is the case with at least one testing regime in the U.S.A., data cannot be extrapolated.
It is also my understanding that the C.I.P., which operates under the supervision of the Belgian Parliament, kept everything the same except for the change from lead/copper slugs to piezo sensors.