AA Ultralight?

[stanc]

If you want to shed weight, I would recommend using an upper without the Forward Assist (something I hate anyway), versus cutting weight on the bolt carrier. The lighter carrier weight could be balanced with a stronger recoil spring, but I prefer leaving things with the operating system as close to optimum and proven as possible.

You can get uppers that are in every way like a flat-top upper, with ejection port and brass deflector, minus the forward assist from Les Baer.

The last thing I need is a stronger recoil spring.

I share your feeling about the forward assist, and in my research over the last week or so, I discovered the Les Baer upper you mention. I thought that'd be perfect, but then the "ejection port size" thread led to the note on the AA site that AA uppers have a "Grendel specific" ejection port.

http://www.alexanderarms.com/gtech.htm

That made me wonder if the LB upper, with its 5.56 ejection port, would be okay for use with 6.5 Grendel. But, some here say the 5.56 port is compatible with the fatter cartridge. If so, that'd certainly be my choice. The down side is that'd mean not only buying a bunch of parts, but finding a good gunsmith here to assemble them into a complete upper.