Is there a post that someone can direct me to with a chart that deciphers markings on uppers for the different brands?  I know I've seen it before, but I'm not getting the results I'd like on the search engine.

Thanks.

[url]www.biggerhammer.net/ar15/uppers[/url]

No, the Bigger Hammer link is very out of date, and all the manufacturer's have been contracting the same forging companies for their upper, and lower, receivers.
Tell us which marks your looking for and someone can post the forging contractor.

Same here. I bought a Carry Handle from a friend that has the splintered "A" and I think a number next to it. Maybe a "1". Do you think it will work with my Bushmaster M4 upper???

It should; since Bushy almost certainly made it[:D]. Sounds like one of the batch that they made as part of an order for flat top uppers for the Canadians.  Bushy assumed they'd want the iron sighted top ends too, so made up a bunch.  In fact, the Canadians planned to mount their ELCAN optical sights, didn't take the top ends, and Bushy dumped them on the civie market a couple of years ago. At least that's the story I saw posted at the time.  Bought one myself. Works just fine on my Rock River upper, too[:D]

The "splintered A" is actually an A and a H, for [url=forgings.com]Anchor Harvey[/url]. Colt, Bushmaster, DPMS, Oly, and J&T Distributing, have all been using Anchor Harvey upper receivers and carry handles.