The two x47's i've had, the trick has been sticking a berger, ELD, or scenar (any bullet i tried) over h4350 or varget (the only powders i've tried) and shooting. I have not tried any load combo with those components that didn't shoot well. In general, i've landed on berger/JLK 140s over 40.0-40.5 gr H4350 or 130 AR hybrids over 42.0 gr h4350. I like the 140 load better because it's not compressed.
Edit to add: Per the OP question about starting load for 139 scenar over h4350 - I'd say around 38 grains is where i'd start. Its worth noting that this case hides pressure very well and the loads I (and others) listed are likely above max pressure. When you start seeing charges exceeding creedmoor book max charge and velocity in a smaller case with less freebore it's pretty obvious that pressure is up there. I've never had issues with it but make sure to use primers with thicker cups.