Lots of good options out there but right now Palmetto State Armory is leading the pack with quality and pricing for general purpose AR's, check out the daily deals on their web site.

Personally I have a 10.5" PSA 300 Blackout upper (registered SBR) that is crazy accurate with 220gr subsonic loads, a 8.5" 5.56 PSA upper that shoots good, no real accuracy testing yet.

Be aware with shorter AR barrels comes shorter life of parts, short barrel 5.56 guns will start beating the bolt carrier and buffer badly after a several thousand rounds, your gun/round count will vary. Good info on bbl length in GT's video here-

https://www.youtube.com/watch?v=9q03ZkC4VUs

Top tier companies like Bravo Company, Sons of Liberty Gun Works, Daniel Defense, too mid level like Aero Precision, PSA, Faxon Firearms to name a few.

Two biggest needs in a upper are a good barrel and a good Bolt Carrier Group.

Or build your own, AR15's are like Lego's for grown ups, they are addictive. My current favorite barrel maker, without breaking the bank, is Ballistic Advantage, reasonably priced but really accurate and nicely made.

Gunner

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41 Mags rule, Baers rock!