is there a peice of broken drill bit stuck in there? If it is it may be breaking the other bits. I broke a bit once doing the same thing. its easy to get it in a bind and break because of the angle. Luckily for me the broke peice wasnt wedged in and fell out when I turned it upside down. I know you dont want to hear this but you may have to pull the gas block to get the bit peice out, but if the broke peice is sticking up past the surface of the bbl it may bind the gas block when pulling it off. If you get it off you can drill it at a 90 deg angle. Just a thought.