If it's for a 12 ga, you could try a published load I use to save on shot and recoil:
7/8 oz lead
Federal 12S0
Remington hull (STS)
Win 209
about 15 grains of Clays (I don't have my book handy to give you an exact number, but it is a published load).

It comes in well under 8000 psi (close to 6000, IIRC) and there should be plenty of room for you to roll crimp it down to 2 1/2. It's a nice, easy-shooting load.

fiery, dependable, occasionally transcendent