same hereDigging bar, have a few myself pointed and chisel tipped. Near impossible to dig a post hole around me with out one.
I dug around 50 or so last summer. Even had a tow behind auger. Auger would go 6 inches and you would hit clay and shale, bust the rocks get maybe another 6 inches and repeat. My only saving grace is that its not many large cobble/boulders, which is like ten times harder to break through than the shale.same here