Custom tech work done by my local techy man (Master TCAA) / Dan Magnuson. He went through and just replaced some faulty weak parts to get me some fps. He used G&P parts to replace to old ones. Outer barrel not standerd withmost Vltors! its a Chrome cqb like outer barrel! Vltor upper and lower reciver with full trades! DD type rails! NO wiggle. PM for more info!