What brand AR15's have barrels with "HBAR" inscribed on them?

I believe HBAR stands for Heavy Barrel as opposed to a 'government profile' 'heavy' 'medium' 'light' 'featherweight'

so what really matters is who made the barrel that was sold to colt and/or bushmaster, they stamped HBAR on the barrel before they sold it.

I build Match AR's.

There are probably 23-27 barrel manufacturer's currently producing 12-17 different types of AR-15 barrels in all sorts of sizes, shapes, metals, and twist rates.

What was stamped on barrels 20 years ago - and what is stamped on barrels today - do not mean the same thing. A late 1970's or early 1980's Colt barrel stamped HBAR would be a 1:12 or 1:10 twist rate for 55gr bullets that is totally useless today when used with the new green tip (62gr) or match (68/69gr) ammo.

There is no shortage of ill meaning people pulling these useless barrels out of inventory, or, cleaning up take offs and selling them as new online to unsuspecting idiots wanting to make their AR look 'Tacticool".

20" barrels came in 'Government Contour", Heavy, and Heavy Match - although some have been lathe down to Lightweight.

It's the twist rate you need to worry about. You Need a 1:9 to shoot today's ammo - and - your are better off with a 1:7 if you have no interest in firing 40gr varmint ammo. With a 1:7 you can handle 62g to 100gr ammo - these are all the new high tech bullets used for long distance shooting, big game hunting, and firing subsonic rounds that still cycle the action.

There is also no shortage of cheap china parts being sold online to US Buyers.

Bottom line - steer clean of any used barrels - unless you have a chance to personally measure the twist rate before putting down any cash! Best to buy new barrels from a reputable dealer, and, have somone who knows what they are doing install it and properly gauge it. Saving $50-$200 on a barrel is not a savings if you have to spend $20,000 to have it removed from your face and twice that from missed work.

I was under the impression that the HBAR is a Colt, I wasn't aware that Bushmaster has an HBAR.