I used to load/shoot .44's a lot. Ruger Super Blackhawk 7.5" and a S&W M29 4".
I used mostly .44 magnum brass and some .44 Special brass. I used Unique for all the lead bullet loads. It's been working fine for many years more than the 42 years I've loaded it.
Never noticed any issues when shooting .44 Special then shooting .44 magnum brass. Same for using .38 Special first/middle/last in my S&W 586 or Ruger Speed Six. Non-issue for me. I mean, I read about it, but it never happened. Sort of like all the "1911's are unreliable" threads. I read them, smile and go on doing what I've been doing.
Now, for the real magnum loads is was mostly 240 grain jacketed hollow points and 2400 powder. I used some WW296 but mostly it was 2400. Might have been some H110, too, but people say it's the same as WW296 (but the H110 didn't split cases like the WW296 did - this was later in my Dan Wesson .44 magnum.)
I tried some 180 grain bullets but never got the accuracy of the 240 grain bullets (jacketed or cast).
I used the soft lead bullets (like those greasy Speer and Hornady bullets) with Unique and light loads with no leading issues. I only used 2400 with the hard cast 240 grain loads which were travelling quite a bit faster than the Unique/soft lead loads.
.44's are fun. They are good for breaking up rocks, shooting through small trees and appliances, car doors, etc.
One day I was shooting an old water heater tank. The 230 grain .45 acp loads would dimple the front and I'd find some of them in the dirt in front/under the tank (lying on it's side). The .357 magnum loads would punch through the front and dimple the back side. The .44 magnum loads would punch through both sides and go on down range to the dirt bank. Don't think you can hid behind a chunk of moderately thick iron and be safe from a .44 magnum.