Changing Ammo/poa

[HANDGUNNER]

I bought some Speer 270 SP for my .44 mag revolver for a bear hunt next week. Sighting it in I'm shootin about six inches high @ 50yds. All my 240 grain ammo is dead on. I've never had that much of a difference with changes loads for rifle or pistol before. I have to go back with another box this week and see how it is under 50yds. I hate to move my sights for one hunt. Anyone else had this much of a difference with ammo?