Pathfinder,
I think all the confusion comes from the .44 Martin, which is the same as the .44 Colt.
Arsenal loaded ammo says for the Colt & Remington Revolvers, they should have said for the Colt & Remington Conversion Revolvers.
I load the .44 Colt Original for my 1858 Howell Conversion with 200 gr. .451 Diameter Heeled Bullets.
The .44 Remington CF didn't show up until the 1875's came out, this I believe is the only revolver chambered for .44 Remington CF.
I didn't post earlier, but I have a bullet diameter of .447" listed.
I'm not an expert on this, but this is how I see it.
AntiqueSledMan