What kind of Flash Hider/Muzzle Break is this?

[BlackReef]

Sorry, I know this is common knowledge to some, but I really don't know what it is. I have seen many pictures with them, but I have never known what they are or what purpose they serve. I'm assuming these are ILLEGAL on a Featureless build, right?

[J_Rock]

its a noveske KX3, otherwise known as the the flaming pig

http://noveskerifleworks.com/cgi-bin/imcart/display.cgi?cat=11

[Sgt Raven]

Sorry, I know this is common knowledge to some, but I really don't know what it is. I have seen many pictures with them, but I have never known what they are or what purpose they serve. I'm assuming these are ILLEGAL on a Featureless build, right?

KX-3. On a 13.7" build, if pinned/welded they bring it out to the legal limit + at 16.1"

On a SBR with 10.5"-11.5" barrel they increase the back pressure which helps with weapon function and it directs the blast down range which raises the comfort level of the user.

It is a flash hider so it's a no-no on a featureless build.

[ar15barrels]

Don't forget the weight they add to the muzzle.
7.2 ounces at the muzzle feels like two pounds at the pistol grip due to the leverage out at the muzzle.