Nominal cylinder throat diameter is supposedly .429, same as barrel groove diameter theoretically is.
Every gun is an individual and must be measuered to know what it is. I have encountered diameters in 44 caliber from .427 up to .434. .429 and smaller is rare, as is .433 and .434 if the gun was manufactured since about 1995. The major variations were prior to that.
A mold that produces .432 bullets will shoot very well in most revolvers, with sizing as required to make them chamber easily.
Please contact me personally about this by email to LBTisAccuracy@Imbris.net
