I'm curious about an upper.

It's a Colt flat top upper marked Colt 223, with an HBAR 1:9 20" barrel, A2 flash hider. Pretty heavy, more so than another 20" I have had. Ribbed handguard.

I can't seem to find information on the variant. I've come across Colt 20" HBAR barrels, 1:9 twist with A2 flash hiders, but they are not flat tops.

No markings on the upper other than Colt 223.
Front sight base is marked "F O 5", and inside the "O" are letters "RI", no bayonet lug.
Bolt carrier is fully neutered and marked C
Pivot and takedown pins are standard.

I suspect it is a Target Competition of some sort, just doesn't seem to fit any of the model variant's I can find information on.

Looked at the table on the often referenced site, couldn't find it
https://www.biggerhammer.net/ar15/variants/
Closest I could find is R6700CH but that doesn't appear to be a flat top.

20” Hbar 1/9 flat top belongs to the 6700 series.

If it has a threaded muzzle I’d say it was made before 1995/1994.

If it’s marked .223 on the upper receiver side i guess it’s a Conversion Kit.


This might help
https://www.ar15.com/forums/ar-15/Colt_6700_data_base/118-271181/

It’s an early ‘90’s Colt conversion upper. The uppers marked “Colt .223” and “Colt 7.62x39” on the left side were sold as conversion uppers only and were not used on factory build rifles.