Typically the BBs rolling out of the barrel means you have the hop up set to zero. I trust you have some hop up dialed in?
BBs not feeding well in full auto............... what mags are you using, does it happen to all your mags? Or you only have one? And how new is the mag? A fix could possibly be just lube in the right places, it sounds like your mag isn't feeding as fast as the gun wants it to.
More info would help others sort out what might be wrong.