Ics Mp5 Fully Auto Firing Probs

[Wayner]

Can anyone help i have just purchased a ICS mp5 a3 sd6,lovely gun but on fully auto firing in bursts the gun leaves a bb in the barrel after a burst,and when you resume fire a new bb hits the afore mentioned bb and breaks it and spits it out in all manner of directions,it seems like the mag loads the barrel up quicker than the gun can rid itself of them. Is it a simple tweak job i can do myself or do i have to send it back?