I was looking at an AR yesterday that had a flat top reciever.  On the ejection port side, top rear, between the charging handle and the brass deflector, there is a small "A" symbol which I assume is the manufacturer's mark.  Anyone have a clue as to who made it???  I Have seen a similair symbol on a Bushmaster removable charging handle, but Bushmaster's flat top upper has a "keyhole" symbol in the same spot.  Also, how can you tell a cast upper from forged???

Thanks

I'm sure someone on here can tell you which forge that mark belongs to, but it only tells you who made the [i]raw forging[/i] for the upper.  As far as I know no manufacturer marks their uppers so there's no way to tell who did the machining & finishing on [i]any[/i] upper.

IIRC Oly has a page on their site about how to tell a cast lower from a forged lower.  Some of that would also apply to uppers, but I don't know of any cast uppers, except maybe the Plinker from Oly, but that's not a flat-top.  

These marks tell who did the raw forging, not the actual finish machining of the part.  A broken up "A" is Anchor Harvey.  The keyhole is Cerro metal products I believe.

I think the "A" is for Alcoa.