According to a fellow who researched Civil War pistol cartridges found that the small powder charges (15-22 grns) used with conicals were about equivalent to 4F, and that the power levels achieved were like that of Swiss.
I find this very interesting as many state that these cap n ball guns are no more powerful than a .38 Spl if using a .44 cal gun. But it seems their findings are based on common powders available during the 60's and 70's, and not on what was available then.
The pine board penetration tests show that what they used was obviously more powerful than the more common powders available, not to mention the military record of soldiers (many) shooting a brown bear with their .36 cal pistols with no real effect until an officer armed with a .44 cal pistol (likely what we know as a Dragoon?) killed it with 2 shots.
If a '60 Army, '58 NMA, and ROA with their similar chamber capacities are only capable of achieving .38 Spl power levels a few more grains make it what, a .38 Spl +P?
The one thing I'm uncertain about is that he compared Triple 7 to Swiss powder as they give very similar velocities when used in the same volume. But does that produce the same pressure and a similar enough pressure curve?
Many state that Hodgdon's states you must reduce the powder charge by 15% as it's much more powerful than BP. But that's not what it says. What it does say is that, because it is more powerful, you'll need to reduce the charge by 15% to achieve similar velocities as BP, which obviously doesn't coincide when using Swiss or Olde Eynsford powders.
I've emailed Hodgdon's several times asking for clarification on that, as well as what many state as not compressing the powder, which is another misunderstanding as their site states not to compress it when loading cartridges. What it does say is that it should be compressed "firmly" when loading muzzleloaders/cap n ball guns. They've not responded to any inquiries.
That said, I'm comfortable loading full house loads in my ROA as I know it's more than capable of handling it, but I'm leery of doing so in a reproduction or muzzleloader of any type.