We didn't know you meant Redhawk when you said Blackhawk. The SBH isn't made in .480, the SRH is.
I've had two of them, and think it's a great caliber. Using a Lee 400 grain cast bullet, I can load anything from "plinkers" up to full power .475 Linebaugh loads for it. The Lee bullet has two crimp grooves, and when using the lower groove the case capacity is the same as the .475. I've used exactly the same load in .480 cases with the bullet seated out as I do in my .475. Mine is topped with a 2x Leupold and has sufficient power and accuracy to take deer size game cleanly out to 100-125 yards.