Shooting a Colt SAA revolver made in 1880's

[shelley1958]

I may be acquiring a Colt SAA revolver made in the 1880's. I understand you have to shoot black powder ammo in these, not modern day smokeless powder. My questions are, where do i find black powder ammo, and also is it recommended to shoot modern Cowboy action cartridges in it, as Ive been told they produce less pressure. Don't want this old beauty to blowup in my hand!