I had a 4-5/8" Blackhawk Convertible years ago (like 20 or so) and wound up trading it for my Bisley.
I REALLY like a 4-5/8" Blackhawk anything, but in the 2 or 3 years that I owned it, I never fired the ACP cylinder. For one thing, I didn't handload .45 ACP's yet (likely the biggest factor), but now (20 years down the road) I usually shoot 286 grain 270-SAA's at 1,000fps out of my Bisley, and can't imagine that an ACP load would hit close to where my sights are at the 25+ yard line.
The Blackhawk was blued with the AL grip frame and ejector rod housing. That plus the shorter barrel made it a lighter, handier package than the Bisley. My Bisley (Bowen tuned) shoots like it has eyes, but the Blackhawk shot very well. The "big bore but handy" niche has been filled with a Kimber 1911 for the last 15 years.
I say go for it. I did like mine.
