Regarding loads for the BPE. I would start with the nitro for black loads listed in Shooting the English Double Rifle by Graeme Wright. And I would use Woodleigh softs, not Hawk, unless it is impossible to get Woodleighs to regulate. But I have always found that Woodleighs regulate easier than Hawks. You could also try cast lead bullets, but if Woodleighs work then I would stop right there and go hunting!