I have a used Bushmaster chrome lined 16" H-bar post-ban. It is the full assembly and includes front sight tower, sling swivel, gas tube and pin, handguards, delta ring, weld spring and clip, and barrel nut. Has about 1000 or so rounds through it. It's still in great shape. $100 + shipping. email@example.com
I have an Oly Arms M4 barrel. Stainless steel, black finish. Marked 5.56 SS. New, threaded muzzle, no lug. Shot me an email if interested. $140 delivered. Or, I have new CMMG 1/7" 16" M4 barrels for $215.