I have a Colt 16" M4 profile barrel for sale. 1/9 twist, has bayonet lug, and threads for flash suppressor. Marked "C MP 5.56 NATO 1/9". Barrel is NOT chrome-lined. Apparently, Colt took some HBAR 16" barrels and turned them down to M4 profile due to extremely high demand. I think it's 1999 manufacture.
Overall, I'd say it's about 95% condition wise. I fired 2500-3000 rds through it, approximately. Accuracy was just fine.
Barrel is stripped - has front sight tower/sight, barrel nut, sling swivel. Does NOT have delta ring, handguards, or flash suppressor. It does have a decent scratch on it, under the handguards, due to pliers slipping while removing the gas tube. But, with handguard on, it does not show.
$150/best offer, plus buyer pays shipping.