I use the Spyder Rapid. It's a pretty good electronic loader for .50 cal. It will do 20 bps and it's only $50.
It's designed for .50 cal markers so it has a thin feedneck, but you can make it fit your Ego quite easily. Just wrap some black electrical tape neatly around it until it's thick enough for your Ego's feedneck to clamp down on it tightly.
Here is a link to where you can find one:
http://www.punisherspb.com/kingman-s...der-black.aspx