When one looks at all the different figures from all the different loading charts, it gives me good reason to go by my own, actual figures, as generated by my own loads in my guns.
Also, one can interchange cast bullets with jacketed bullets, in the 44 magnum.
I used to compete in silhouette shooting with big pistol and have owned and used extensively, five different 44 magnum revolvers, as well as having two different Marlin rifles in 44 magnum.
So here are some things I've learned. I have shot many different bullets in the 44s. Sponsors of silhouette shooting were forever giving us samples of different bullets to try. They were all 240 grain jacketed, usually full metal jacket, as well as all my own cast bullets of either Keith pattern, the 429421 or the gas check cousin of it. My "240 grain" cast bullets never weighed as low as 240, and went as high as well over 250, depending on the alloy they were poured from.
I used the same maximum load for every bullet I shot in any 44 magnum, revolver or Marlin rifle, 22 grains of Hercules 2400, or 25 grains of either H110 or W296.
There is a lot more effecting velocity of a revolver bullet than just barrel length. The biggest loss is the pressure escaping from the gap between the cylinder and the forcing cone, and this varies greatly between individual guns. This is why velocity in a rifle will be 250 to 300 fps faster than a revolver.
Here are some samples from various revolvers, usually a Ruger Super Blackhawk with 7 1/2" barrel.
24.5 grains of H110, 252 grain flat base bullet.--1323.
22. grains of H110 " " " " " 1188
20 " " " " " " " 1126
22 grains of 2400, 252 flat base bullet------- 1415
20 " " " 1312
17.5 " " " 1120
24.5 grains of W296--gas check bullet weighing 265 grains---- 1385 fps.