I don't have a 45auto cyl for my Ruger but you will not hurt your Blackhawk shooting 45Super through it. I have shot a load in 45LC with a 335 grain cast bullet at 1193 ft/sec without a hiccup so I don't think any super mag cartridge is going to pressure test it in any way.
To some extent the answer depends on which BH you have. Is it the full size or the flat top? If full size then it's tougher than anything in the acp case. If it's the flat top chances are it's still up to it but I don't know what pressures the 45-SMC or 45-Super run at. The flat top is NOT as strong as the full size BH.
Bill aka the Graybeard
I am not a lawyer and do not give legal advice.
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