Get a whole shooting platform for less than the full upper. It's darn accurate and great to use iron sights on a soft shooter.

Brownells 20" complete upper (BRN16A2), these are $799.99 from Brownells website
>All new production, no surplus parts
>M16A2 Upper Receiver
>A2 USGI Rear Sight Assembly
>20" 5.56x45mm NATO barrel with 1-7 twist & chrome bore and chamber
>Mil-spec bolt carrier group with phosphate exterior and chrome interior

KE Arms complete monolithic polymer lower. Yes it's strong enough. Yes, I've fired it with no problems.
Battlearms Development enhanced trigger

If the ad is up the rifle is available
I am near the Chandler Airport

https://www.brownells.com/gun-parts/rifle-parts/rifle-receivers-parts/brn16a2-5.56-20-complete-upper-receiver/

https://www.kearms.com/kp-15-polymer-receiver-milspec.aspx

Trades: 11.5" AR pistol , something that takes 17rd Glock mags, lever gun, 1911s, something interesting. See my other listings.