I just purchased a AR15. Preban Eagle Arms A2. Heavy barrel with snap-on 5.5" flash hider. The flash hider is not an extension of the barrel it covers the 16" barrel and the barrel ends wjere the slots are on the flash hider. So I have the look of a XM177 without losing the velocity of the 16" barrel. I think its pretty cool. It also came from Colorado, out of all places. Anyway, just wanted to share.