Im doing load work up on mine too, using H100 and Retumbo. Ran out of bergers trying to get them to fly... Havent decided if ill try again as im not hearing about anyone having much luck. Im now running 285 hornadys. H1000 had a sweet spot around 87.5gr in mine, but ive heard people are havibg good luck between 90-94gr. I loaded up to 92 without finding anything great. Thats above listed max though so proceed with caution.
i just got my hands on some retumbo and started working it up. Dont have my log book on me but it was shooting very tight throughout the range i had it loaded, which was low to mid. Well i cant say very tight, horizontally it was around .7 edge-edge(not bad for initial workup), but vertically it was 1.25-2+.... Ive since adjusted my scope mounts so the crossbar of the rings pushed forwars against the rail as ive been told that will cause vertical stringing. Ill be taking it out tomorrow or sat to see if that was the problem. On dan newberrys OCW site he has a couple suggested accuracy loads for it you may want to check out. hope this is of some help, wish i had some solid data and proven loads for you.