You didn't give the bullet weight. I use that load for 158 gr, either lead or XTP. I bumped up the 125gr XTP load for the smaller gun ( SP101) to 7.0 gr. I haven't tried the mag primers but have them and might check it out.
OOPS. That's a 158 grain Rainier round nose flat point (RNFP).
The mag primers do seem to make it burn more completely. It's rare to find even one kernel of unburned powder with mag primers and 4756.