The case head separations were most likely from shooting Iraqi ammo. Take a close look at some when you get a chance. Try it again with steel cased ammo, and I bet it works fine.
The stuff I had was crap, shittiest brass I have ever seen.
..and one more thing.. that magazine you have in that rifle? People on this board will give you a serious reach-around for it. You could probably get $300-$400 bucks, maybe more.