I have Z5 I experanced similar results, tried APP [Iam trying all the new powders]
and Gold [I have Pinnicle have not got to it yet] with the APP and Gold[ I can not tell any differance between them except price and color]
They shot good; I am inclined to believe from the lead in the barrel the BM3 that it was so fast it strip the rifleing even with light loads.It might work better with a gun that had deep rifleing, the Omega is more or less designed for sabots I think.