I've got a buddie asking me about the 7.62 uppers because hes set on a build.  I'm just curious how reliable and finicky the rifles are in the ar platform.. I've read they need firing pin and extractor upgrades, the right barrel length and gas port to cycle correctly and that the mags and feedramps sometimes cause some problems as well..

Really whats the optimal set up for this cartdrige: gas system, barrel length, what buffer and buffer tubes?

I tried to talk him into an AK because all he want's to do with the thing is plink away with the cheap bulk ammo. I mean I solved this problem with a 350$ wasr that I could care less about. This guys got more money then time so he doesn't care one way or another.  He's really set on a dissapator build aswell. No disrespect to the BRD but can the AR be a resonable platform to dump mags of crap 7.62 realiably??

Trust me when I say just get an Upper from AR Proformance. IT will save you a ton of cash in the long run. I have been working on my build for over a year to make it work right and in the end I have an upper from AR Proformance with a D ring on the extractor spring. I ran over 2,000 on Sat with out 1 single prob and had 6 differnt kinds of cheep ammo in it. .17 cents a round Ya I love it. If your guy has a lot of cash then he should buy the lower from MGI because it can use AK mags and put on an AR Pro upper and you wont have any isues. Hope it helps.

The following configurations run fine for me:

Model 1 Sales 14.5" barrel, carbine gas, LMT bolt, Model 1 enhanced firing pin, Geissele trigger and a Spike's buffer

Bushmaster 16" barrel,  carbine gas, LMT bolt, Model 1 enhanced firing pin, Geissele trigger and a Spike's buffer

AR Performance 16" barrel, mid-length gas, AR Performance bolt, std. firing pin, Wilson TTU trigger

I did have an MGI bolt that broke its extractor, but the above combos have been trouble free and fire steel case ammo and the good stuff. Soft point ammo can be problematic, and the M4 ramps are beneficial because the taper of the round tends to give it somewhat of a nose down attitude in a loaded magazine.

With an ARP barrel and super bolt coupled with current production CP mags, 100% functional with Wolf, Silver Bear, and Winchester ammo.  I have a couple thousand rounds through it now and not that first hiccup.

+1 on the AR Performance upper.