That alloy worked very well (amazing, actually) for me with BP loads in my .50 Alaskan.
With a GC, it should be OK in the 9.5 up to 1,600fps or so.
The not-so-old automatic GO-to load nowadays is a full case to the bottom of a seated bullet using Trail Boss.
Another go-to load is Ed Harris' 13gr. Red Dot shotgun powder. No filler.
That's an old recipe for most ALL calibres .30 and over, .ie: .308, .303, .30/06 and larger.