Accurate clarifies load data changes
I thought folks would be interested in this. I inquired through the accuratepowder.com web site:
I received the following response:
Edition 3.5 of the Accurate load data pdf has significant changes from edition 3.2.2. Specifically, in 3.2.2 for 357 magnum 158gr XTP with #9 it shows a starting load of 13.5 and a top load of 15.0 gr. But in the 3.5 version of the manual it shows a starting load of 12.4 and a top load of 13.8. That’s a very disturbing change, both on the low and high ends. Can you help me understand what justifies the difference? Was the earlier load unsafe? Is the newer load just more conservative? Or did the powder change? I’m sure the ”right” answer is to use the newer numbers, but I need more information than that if I am to trust these newer numbers. Thanks!
It’s actually all about the SAAMI standards for the 357 Magnum.
There is no correlation between the old CUP pressure specification (<45000 CUP) and the latest Psi specification.
Since we only test with the latest equipment the data was adjusted for the lower <35000 Psi limit.
The irony is that the older data will still be safe.
Also the international CIP spec which makes more sense and is closer to the older/original level is <43500 Psi