Well, I've got one set up as my anti zombie ordinance right now. There is nothing fancy about them, just a bare bones A1 upper with a light contour barrel. Mine has been flawless as far as feeding goes and while not a 600m high power gun it is more than capable of giving an excederin headache as far as I can see the target. I've done some tweaking with mine. I changed out the silly fixed telestock for an ACE stock and put an ERGO grip on it. I also mounted the First Samco handguard and mounted one of my m3 lights on it. This gun balances so well for me that it seems tp almost aim itself. I couldn't be happier with it. I may add a real telestock if the ban dies, but I really like the ACE thats on it.