So I think for my first AR I am going to pick up one of these bad boys from DPMS, specifically the DPMS Predator bull 20. They are a little heavier than I had hoped but I suppose that wont matter too much since I am going to put a bipod on it right away. My question is what barrel length would you guys suggest. I was thinking 20" is the best way to go due to better mobility than the 24" but was curious what you guys thought about the 24" versions. I'm pretty new to this whole thing and don't know a lot about this stuff, slowly learning. I'm heading to the gun show here in Portland and am hoping I can find one of these or perhaps a Rock River Predator Pursuit. Cheers!