There is also the factor that nowadays, people think nothing of loading up conversion ammo with smokeless ammo where 10 years ago that would have sicced the Black Powder Po-lice on ya...using the justification that "as long as you stay within black powder pressures..." which ain't necessarily so! Even if you keep MV below, say, 750fps, the pressure spikes and resulting bell curves are very different from smokeless and black powder cartridges producing nearly the same MV. And on smaller, thinner-framed pocket guns, it might be enough to make a difference, even if the cylinder itself is up to the task.