you might want to look into a palmer brass barrel. I have heard nothing but good things about them. I have an E-grip on my A5 and I love it. I will say it is easy to chew up some air and some balls. I am looking at buying a Richochet R5 Hopper based off the reviews from other members of the board. It does hold more balls than the stock hopper. If you are going to be looking at high ROF then the Vortex mod for the cyclone feeder might be in order. My A5 with an E-grip I chewed up a 20oz CO2 tank in one game and shot maybe 900 balls. The game did last 2 hours though.

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A-5 w/ E-grip, Flatline,Palmer Brass, Lightning Rod, remote, Air-Thru SAW Stock w/Palmer Reg, and 48oz tanks!