I kind of expected they wouldn't have any specific info about pistol calibers, since ballistics is normally focused on long range performance (often over 500yds), and pistol ammo simply isn't effected to any significant degree by things like barrel whip, spin drift, and so on. But at least you got prompt reply.
One other thing I'll mention is the barrel length on your Henry. This was a topic that came up a couple years ago, and there was a lot of confusion about it. Henry used to measure barrel length from the muzzle to the forward end of the chamber, which meant that your 17.4" barrel is actually 16.4" long (approx) as seen by the bullet. They switched to the ATF method of barrel measurement a few years ago, which is from the muzzle to the closed bolt face, and presto your barrel became 17.4" long. This was convenient for the ATF, but if your concern is the actual length the bullet see's you need to use that shorter dimension, as it will make a difference in some ballistic calculations.
It makes sense if you think like a regulatory agency, since it allowed them to make a blanket rule that covers all rifles, pistols, and shotguns regardless of chamber length & caliber/gauge, but makes no sense if you think like a normal person who understands that what counts is what the bullet sees. The only exception to that rule is for revolvers, since the barrel of a revolver does not include an integral chamber.