Bear in mind that my heavy experiance with the 30 carbine pistol was with a single shot which would stand 60,000 pressure, so my real heavy bullet talke has to be taken with that in mind.
For the Blackhawk 30 carbine I expect 130 gr would be a good maximum weight, but I'd have to have cylinder throat length measurements to be sure. The ammo cannot be crimped, because the case headspaces on the case mouth, so real heavy and crimped bullets are out. 120 gr for sure will work well and I believe one could expect at least 1500 fps when loaded with 296 or H110 to capacity.
The best source for lead bullets is to cast your own, but if you don't, try MontanaBulletWorks.com I believe he has at least one 30 caliber mold which would be suitable. If what he has is a bit lighter than 120 gr, you'll get more speed, but the same power, as power is determined by how much powder is burned. Within limits of coarse. What I'm saying here is, with any revolver, a few grains in bullet weight either way doesn't matter on target. Big changes in weight and target/or impact, results change dramatically.
