Here's the deal: Manufacturer: Bulldog (google them) Condition: New, unfired 16" length 5.56 Chamber. 1-7 Twist Button Rifled 11 Degree Crown Threaded 1/2x28 Polished Chamber M4 Feed Ramps No Chrome Lining Lightweight under the handguards Just the barrel, no barrel nut, or Gas Block/Sightbase Uses the carbine length gas tube $180 each + $10 shipping (I can stuff 5 barrels in one flat rate box). What I have is what I have. That is all. I don't have any 20", middy, 1/8 twists, etc. This is it.