AR question

[superdown]

I keep seeing the ad on the forum here for an ar barrel that is 11.5 inches long with a flash hider / muzzle brake that is like 5.5 inches long to make it legal. i understand that it is to make it a legal length. But my question is why not have rifled barrel for the whole length besides what the effective part of the muzzle device takes up?It just seems stupid to me to throw away what ever velocity you may gain    

[Biggerhammer]

Someone just wanting to sell their pile of 11.5's. Without having to go the "SBR" route.

[actionshooter]

The only reason I could see is if someone wanted to build a XM177 clone.

[b23]

Hmmm, what if you replace that 5.5 flash hidder/muzzle brake with a 5.5 or longer surpressor, are you still within the law or does that make it an "SBR"  

[jay.sharkbait]

Hmmm, what if you replace that 5.5 flash hidder/muzzle brake with a 5.5 or longer surpressor, are you still within the law or does that make it an "SBR"  

The suppressor would have to be permanently attached.