Kosh, have you tried any of those loads you posted? I'm not a fan of the safety first drones, but that 23 grs of 2400 sounds less like a cartridge and more like a pipe bomb.
No, I haven't. I'm in agreement with your assessment. As I said, I would be willing to try these in a Marlin or Modern Winchester. I Wouldn't get NEAR these loads, in a Henry.
Even so, Elmer Keith hot-rodded the .44-40 considerably, but finally gave up because because excessive chamber length stretched the cases and shortened their useful lives. If memory serves, the two loads he arrived at were 18.5/2400/205 cast & 20.0/2400/205 cast (I think the latter was for balloon-head cases, but not sure).
The loads I posted were from another site, posted by a contributor whose work I do not know.
I DO NOT ENDORSE these loads. I merely report them in the interest of examining ALL the information I can find, not just what's convenient to examine.
I HAVE tried analogous loads in a Rossi M1892 Carbine chambered for .45 Colt (18.5 - 20.8/2400/250 RNFP). My SHOULDER started showing signs of incipient catastrophic failure way before the carbine made a whimper. And I wouldn't try THOSE loads in a Henry, either.
There being not that much difference in the energy of a 44mag pistol and 44-40 so 44-40 is as viable as any pistol,caliber.
I'm guessing that you meant there's not much difference between the .44 Mag from a pistol and a .44-40 from a rifle? From revolver barrels, they're two different cartridges. The .44-40 more resembles the .44 Special than the .44 Mag.
Back to the point: I'd bet with confidence that many a home and hearth has been ably defended by a Henry rifle, whether within the domicile or at its exterior. It might not be IDEAL for inside use, but were I a would-be aggressor, I would not fail to take it very seriously.
Additionally, if you buy the Henry and find it wanting for indoor defense, then it might be considered your "moral duty" to procure a sidearm in the same caliber! I know it'd be a chore to have to buy ANOTHER fine firearm, but a man must do what a man must do.