The largest problem is his bore size, he needs to first find a sabot and a bullet to suck up the space provided then move to the powders. I think his bore is lager and yet he stated he is using sabots and bullets know to be smaller?....Counterintuitive.
If it were me I would first slug the barrel and measure it out then move from there.
In my CVA I have a slugged measured .503 barrel so because of this I use a MMB HPH/12 sabot and a larger .453 250 grain T/C Shcockwave (Hornady 250 SST) bullet coupled with 120 grains of BH209 and a CCI 209M Primer. She loads a bit tight but shoots 3 shot MOA at 100 yards so who cares.
In my Knight it has a slugged measured .5025 barrel and it likes Harvestor black Crush Rib sabot, 250 grain Hornady .453 bullets, 120 grains BH209, and CCI 209M primer.
Using EZ load sabots is not good, especially for smokeless. If it were me, and saying this from no actual experience in the Savage, if I were to start some where and through money at it I would pick up a bag of MMP HPH/12 sabots and some 250-300'sh grain bullets of your choice, some Hornady .453, some .451 Scorpion PT Golds, or even some .452 Barnes bullets. That will give you .003 variance just in the bullet differences. Then play with some of the sabots. You could also move to a .458 bullet and run a tighter .452 MMP black crush rib sabot as was posted pervious.
