With all purchased Tippmann A-5's, a certain thing called a cyclone feed is included. I believe the A-5 is the first paintball marker to come with a paintball feeder making Tippmann the creators of this very helpful feeder. This cyclone feed system functions with air as you pull the trigger. After the bolt has pushed the paintball out of the chamber, as it returns to its normal position air goes threw the cyclone feed and pushes another paintball into the chamber. The newer models of the A-5 come with a feed rate of 17 paintballs per second.
Although this is a great use to the A-5, you will probably be better off buying a "A-5 Shaft and Ratchet Kit" that goes inside your Cyclone feed. The stock part that you'll be replacing often wears down because of its materiel.
Sure 17 paintballs is a fairly fast for those who play it tactical and smart, for the people that rather save there paintballs and shoot more precisely; BUT those are preferences I guess. Some paintballers do need a feeder that loads up to 30 paintballs per second. Well for their case, there's always the "Q-Loader" which feeds 30 balls into your marker, per second.