If you want the bonecrusher to be accurate, you need to fight monsters you can easily one-shot, preferably with range/mage so your character don't actually moves.
I suggest chickens with a sling, but that might be suspicious to Jagex.
ahh yea, has anyone done this, if so what are the exp rates like im hoping for around 10k as thats probs 100k pray exp per day since ill be botting 10hours a day