We found some 585 hardcast, sized and lubed bullets.
Works ok in my 585s at high speed. Shown in picture.

We showed 10ga slugs above, Another easy to do
10ga slug load is the 10ga wadcups for lead BPI has,
with a 69cal swaged lead bullet in it that Dixie sells.
It is hollowbased and 750gr.Also use the same wadcup
for buckshot. Some are showing interest in 10ga
due to NEF making them with heavy bull barrels.
Another experimenter has got a bunch
of RMC 3.5" brass 10ga cases, and will load and test
the fullbore 10ga slugs shown above. RMC can do
them about any time you want.Ed