Now we all know H110 and 296 are the exact same powders but different lots are sent for WW 296 and Hodgdon H110. Small difference maybe but H110 was superb in the RH but 296 works better in the SBH, SRH and S&W 29. I could never explain it.
I found in all conditions the mag primer always tripled groups for me. You might want to use them with H110 but no other powder needs them. H110 does not need a mag primer in the .44.
The problem is that mag primer pressure can move a bullet out of the brass before good ignition and that changes case capacity for every shot.
Many companies have found the same thing and have reverted to standard primers and Fed told me they do not have any records of using magnum primers in the .44.
To the nitty gritty, some guns like one powder over another.
