Ballistic Advantage 16" 5.56 M4 Profile, Modern Series - $83.18 + Free Shipping

I wish AR-15 manufactories, barrel makers, and dealers would stop promoting carbine length 16 inch 5.56 barrels. The DOD developed the carbine-length gas system to work with the 14.5 inch M4 barrel, to render a more compact combat rifle. Federal law requires civilian rifle barrels must be no less than 16 inches in length. You can buy 14.5 inch barrel, but you have to permanently attach a muzzle devise to meet the 16 inch legal requirement. Many knowledgeable AR-15 shooters have. Others use adjustable gas blocks, or heavier buffers to mitigate the over-gassing that commonly occurs in 5.56 carbine length 16 inch barrels. Around 2009 mid-length gas systems appeared in the civilian market, and gave civilian shooters a simple solution, that optimizes gas system performance in 16, and 18 inch barrels. DOD also appears to be moving in that direction, since testing has shown mid-length systems promote longer service life, more manageable recoil, fewer component failures, and more dependable cycling. Before you buy another carbine length barrel, I highly encourage you to give upgrading to a mid-length gas system serious consideration.