10 gauge loading question

[J.B. Books]

I don't know that you can achieve that goal of 7000 psi. I see a 1 1/4 ounce load of lead using 29gr of 7625 and folded crimp in the Rem Blkltr hull, it develops 5900 psi. 1 1/4 ounce of Bismuth in that hull with 29gr of 7625 develops 5900 but uses a roll crimp. My guess, and it's just a guess is you would be around 8000 psi with 29gr of 7625 and Nice Shot, probably lower if you use a roll crimp. You would have to send it out for testing to confirm it.

[George Lang]

Pete are you saying that Nice Shot would have higher psi than Bismuth? It would appear that 5900psi minus approx 600psi for roll crimp plus 1500psi for nice shot should be about 6800/7000psi, or am I missing something? I've only recently started to load for shotshells(0nly 10 ga so far) and I'm sure that there must be more variables then I'm familiar with at present. That's why I'm asking I need to be educated and enlightened. Thanks.

[J.B. Books]

The difference betwen equal weights of Lead vs Bismuth is the height of the shot column and amount of surface area in contact with the bore. 29gr of 7625 is 29gr of 7625. With the lead load you generating 5900 PSI. Nice shot has the same size shot column as lead, but because it's harder than lead it generates more pressure as it has a harder time squeezing down through the forcing cone. This puts you up around 7400 psi with a fold crimp. Using a roll crimp will drop pressure, maybe 600, maybe 800 maybe even a 1000. Only testing will tell for sure. I would stay with the low pressure lead load and add 1500 psi. I can't imagine a sound Parker 10ga having an issue with an 8000 psi load. If you go too low you risk bloopers, especially in cold weather.

[J.B. Books]

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