QUESTION..
 

My go to load for upland hunting consist of a Cheddite hull with Cheddite 209 primer, 18.5 grains of IMR SR 7625, pushing 7/8 oz. of lead shot in a SG16 wad. I use 7-1/2 and 8 size shot.
I would like to substitute the lead shot with bismuth for duck season. I would be using # 7 shot.
Is this safe to do?? Do I need to change the amount of powder? Does bismuth load the same as lead? Do I need a buffer to load bismuth? Looking for advice.. I can probably get a book from Ballistic products but I figure this is way more fun.
16 ga... 2-1/2 inch shells

I loads differently - Mark will chime in - he loads all that hunting stuff.

Your load is a low presure load ( guessing 7000 psi or below ) Bismuth will give you a taller shot column and more pressure . Using Bismuth in that load shouldn't give pressures above 11500 psi . Probably a lot less , but estimating what the actual pressure would be is just a guess without getting it tested .

That same load would work with niceshot .

personally Angel- I'd pop for a book

why risk it

i know that nice shot says to use a lead load and plan on 1500PSI increase

I am not sure I have seen a formula for the difference with bismuth

or at least- pick a low pressure lead load - make a few up and send them out to be tested

The only load that I could find for reference use a different wad and a 2 3/4" hull .

Win poly hull (same as Ched ) Win 209 - 22gr 7625 -Z16 wad - 7/8 oz bismuth 1264 fps - 7400 psi - Precision reloading

I find the z-16 wad will usually give lower pressure for the same load using the Sg16 wad

Thanks a bunch guys. That gives me something to think about. I guess I better see if Ballistic has a book with some recipes.
I guess going from 2-3/4 to 2-1/2 would increase the pressure? Can I go with 3/4 oz of shot instead of 7/8?

Angel you can use 2 3/4 inch reloading data in 2 1/2 (preferably 2 9/16th inch) shells if you want to go to the trouble of roll crimping as the 2 9/16th roll crimp shell has the same interior volume as a 2 3/4 inch folded crimp shell.

Thanks Steve...

Hoe does IMR SR-7625 compare to Green Dot and Unique?

Angel as I understand it they are doing away with SR7625. If I were going to develop new loads I would try powders that aren't going to be obsolete. JMHO