My wife carried a .44Mag for many years. She has taken a few Whitetail, a turkey, one Black Bear, and a couple of Wolves. I killed one Moose with it and a friend borrowed it to kill a Moose in his yard. I started Sky out with it, but after one month his Mother upgraded him to the 45-70.
My Dad shot a .444 Marlin for many years, but it proved to be too much gun for him. He was a skinny tall man, that never weighted much over 160 lbs at 6'1". Dad gave it to my brother, who has used it to take many Deer, Turkey, and Coyotes.
If you are only hunting Whitetails at 100 yards or less the .44 Mag will do the job. At anything over that I would go with the .444.
Got to thinking about the guy that borrowed the wife's .44 to shoot the Moose. When he came up to borrow a gun, she opened the vault and let him pick what he wanted, thinking he knew what he was looking at. He passed a 45-70, and a couple of 30-06s, to reach the .44 Mag. He picked it because it was a lever action, and he was familure with it. Later after he had killed the Moose on his door step, he came over to return the gun saying it only took one shot. A few days later his wife mentioned his shooting the Moose on the front walkway, and all the blood that would be staining the walk come spring. He cut her off saying "one shot killed it". She then commented, "What were the first four for, to weight him down so he could not run away"? The truth came out!
jr 1968: Google "Trail Boss" or Loads for Cowboy Action Shooters" and there should be something there you can use. Many of the Cowboy action shooters use a .444, and download for their compatitions.