Thank you for your explanation. This is making more of a dent in my understanding with time (line upon line, precept on precept, here a little, there a little). I recently picked up, (from Ballistic Products) a 2024 Hodgdon reloading document full of recipes using more readily available Hodgdon family powders (Hodgdon, Winchester, IMR, Accurate Ramshot), that include not only FPS, but PSI for each recipe. Separately, I learned from RST that their low pressure shells made for old guns like ours, never have a PSI higher than 7600. Using that as a ceiling I’ve been able to identify a number of recipes for 12 & 20 bore, and to a lesser extent 16 and 410 to start with.

I’m sharing this with all of you to ensure that my logic and process approach is sound.
Thanks for your help.
- Doug


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