Try gas checks with those high pressure rounds.
Every thing said about bullet fit is correct.
Also try using 2400 (or 4227) and maybe tone down the velocity until you find that golden load.
My most accurate 44 mag round is 18-19 grains 2400 and a Cast Perf. 260 WFNGC.
Have not tried it in a carbine yet but does everything I want in the Redhawk.
Having said that, I am no Elmer Keith and am not going to shoot iron sights at 100 yards.
50 yards would be my very outside range with any handgun.

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NEMO
"Everything 44"