expert so it actually seems confusing to me. Looking at usual dimensions given for bullet diameter, case lenght and OAL, you should be able to use .38spl., and .38 Colt Long & Short both. They all take a .357 dia bullet and with the 38spl having the longest OAL the cyclinder chambered for it should accept the shorter rounds. When you look at the Smith&Wesson .38 I note that it takes a .359 dia bullet, which is to big for these conversions. So why stamp S&W on the barrel? The Italians trying to confuse me?
The main point is that there is a difference in the barrels between manufactured conversion reproductions and barrels originally factory produced as C&B and then converted by aftermarket means (Kirst, R.D., etc.). The latter is going to have it's rounds dictated by the cylinder dimensions and is where you typically have to look to using heeled bullets to seal a larger bore.