C Products is getting ready to issue a 30 rounder in SS with Black Mar Lube. Is gonna be the new standard for mags for 7.62 AR as LARRY is da man. If you are looking for 10 rounders, there is a company called MWG that makes one.
I know that CMMG Inc carries one.
And I will get trashed for saying this, but USA mags make a 10 round Colt Sporter AR mag in 7.62. I have had moderate success with them as well.