From my own personal experience, 400rnds is not enough for 30mins of play. I run with 6 Dye Lock Pods which I believe to carry 160rnds each and my Hopper carries close to 200. I play at Skirmish USA most of the times and I play mid field in all our tactics. Yes, I do use a E-grip set to 10bps and I run through paint like water. Playing a supporting position requires me to lay down paint to keep the enemy's head down so they can't see that we're moving in on them/flanking. Don't get me wrong, I pick my shots also but when called to cover a person...yeah, my hopper goes dry in minutes. So, if I can run through two pods and what was in my hopper in close to 10minutes, I wouldn't last 30mins with 400rnds.