I had one. I simply bought a brand new clyinder in .455, a extra crane, and my gunsmith reamed the clyinder to .45 colt, fit it up with the extra crane and I had a true 45 acp/ 45 colt convertable. He also did other work on it like adding S&W target sights, made a colt trooper type ramp, beavertailed the hammer, I added S&W target grips. Like a fool I traded it for other fine guns back to the friend I got the original gun from. This was around 1970. When my smith got through with it, it looked like the factory had done it! I doubt the gun and entire job cost me $300s in those days!