Dave, .452(Lee .451 mold)is what my ASP likes, chambers measure .443, grooves about .450. New Euroarms may take the .454, I have pressed .457's in it with the wide chamfer hey went in ok. I have the 1858's from ASP an Old one chamfered alot(I like that), a Pietta which I would call slightly chamfered, and the Uberti which is chamfered about half that of my ASP(Euroarms). Euroarms/ASP would be my overall choice, but I do like um all best in their own way. The Pietta does have more room between the triggerguard and the grip than the Uberti but it doesn't bother me a bit...I like the dovetail sight and loading lever release of the Uberti...there's a chance of dimple in the barrel groove with the soldered in sight of Pietta's but that doesn't often happen(if that's a problem to you). ASP/Euroarms more authentic chamber to barrel closer tolerance. Pietta second and Uberti third. Size wise as far as I have found out the ASP/Euroarms closer to an original.
Maybe Mec can shine some lite on the size of an original in comparison.