See this thread: What year did "smokeless" .32 short frames start? Posting #4.

But I don't believe it will help your case much. The S&W catalog pages don't mention anything about design of guns for BP vs smokeless ammunition. In fact, back in the days when the only propellant available was black powder, one could say factually that guns of that time were designed for black powder, not smokeless powder, ammunition. When smokeless powder and cartridges loaded with it first appeared on the scene in the early 1890s, nothing really changed regarding handgun design and metallurgy, especially concerning the commonest top break revolvers available from many manufacturers. A S&W .38 DA revolver made in 1910 remained very much the same as a S&W .38 DA revolver made in 1880, so in that respect the revolver made in 1910 was, technically, one designed around the use of cartridges loaded with black powder. But by 1910, smokeless powder cartridges had largely (but not entirely) pushed black powder cartridges in almost every caliber off most dealers' shelves. What had happened was that smokeless powder cartridges were designed for use in the old black powder era revolvers (as not much else was available to shoot them in at that time), not vice-versa, loaded with smokeless powder to equivalent pressure levels as the same cartridges loaded with black powder, and therefore were effectively interchangeable with them in the existing old guns of the BP era. And that remains true today, as there are still a great many guns which were designed and/or made in the black powder era which are still being fired by their owners with smokeless powder cartridges. None of that discussion helps your argument, but maybe someone else can come up with an interpretation of the the facts which does. Or by finding some manufacturers' (ammunition or gun) documentation specifically stating that older guns were not designed to use smokeless powder cartridges which are too dangerous to be used in them, which would be more convincing. But I have never seen anything like that.