The DPMS runs fine. DPMS is making frankenmags again. When I bought mine, I posted the price and part number, so it is in the archives somewhere. The frankenmags are well made and run like gangbusters!!
They hold over 30 rounds, but I can't count much higher than that.
I have heard that the bolt will eventually break, because a bit of material is removed to allow for the larger case, but it hasn't happened to me, yet, and if it does, I won't mind buying a new bolt.
I can hit the silhouette targets out to 300M with the irons on a 20" bbl. Groups were very reasonable, but it has been a long time since I punched paper with it. I don't see the AR platform as a bench rest rifle, so I don't get hung up on sub MOA groups, particularly with cheap Ruskie ammunition.
Get one, it is well worth it!!!