Hey Flat....
Here's the deal on the 7.62 upper concept. I took my Oly Arms PCR-4 lower and put a 20" post ban DPMS upper assembly from Del-Ton.com on it, and it worked freakin fantastic!! I wanted a little more punch for hunting in the scrub forests of Wisconsin (as a .223 deflects pretty easy in the scrub), so I dumped my old SKS and went this route.
With Federal ammo, it shoots 1.5 moa at 100 yards. With handloads that my buddy makes, it shoots .75 to 1" at 100.Can't complain with that.
If you are a 50 rd in the clip kinda guy, you're gonna have problems!! I am using just the USGI stock .223 mags and load around 6 shells without a problem. Other guys have posted that there are hi cap mags available, but I have no first hand knowledge of them.
Right now I have over 500 rounds through it and it has not failed once!(I like to make sure a rifle is broken in before I depend on it.) I chose Del-ton for the only reason that they had it in stock!! Oly Arms was out 8-10 weeks and local DPMS guys didn't have any either.
All in all...GREAT setup of you don't mind 6-10 in a usgi clip. I don't mind so all is well.
I would definitely recommend this setup for the hunter who likes the ar-15 feel, but either can't or won't use a .223 on whitetail.
This setup has 5 deer to it's claim this year already...none of which moved from the spot they were standing in.
Good luck to ya.