I agree it is doubtful that a nitro conversion would also replace the barrel on grounds of expense, but when I wrote I was thinking particularly of the modern products typified by the inventive Mr Westlake. Some are m/l conversions of S5 handguns and I believe that some are made entirely by Mr Westlake. I have no specific knowledge but it seems to me that either could have a twist rate more suited to bullets. Irrelevant to the thread as it turns out.
Back to the thread - it occurs to me that there might be some difficulty in inserting a bullet using the built in rammer arrangement because there is insufficient clearance with the rammer fully raised. It would still be possible to load the cylinder off the gun and various contrivances are available (or can easily be made) to facilitate this.
WRT "man thing" - a bullet will allow less space for powder. The ROA with ball and a maximal charge of BP (IIRC about 40 gn) produces an impressive bang, a clearly supersonic ball, and prodigious amounts of smoke
I guess the 230 gn bullet will give lots of recoil but there will perforce be less powder behind it so perhaps not so testosterone inducing?