That load should be perfectly safe in your gun. I've got an old reloading manual that lists 4895 loads, 50 grains max for a 130 gr. bullet and 53 gr. max for a 100 gr. bullet.
I'm guessing there's 44 rounds loaded in the bag. I suspect that "duper" = "deeper" and the guy loading them was apparently trying some different bullet seating depths, perhaps to improve accuracy.