I'm trying to find out if the Carbon 15 upper/lower are available from Bushmaster and if enough of the parts interchange with the standard AR to build a 6.8 SPC upper. I'm not real familiar with the Carbon 15 other the weight and want to make sure it is both available and an option for the build I want to start.

I'm planning on doing the following:

16" Douglas Stainless 6.8 barrel and matching bolt
PRI Gen III Tube and rail system
ARMS 40L BUIS
PRI Flip up Front
Chip McCormich Trigger
Bush lower parts
Tango Down Battle Grip
Magpul M93A stock

Lowers are available. They come with the stock, buffer tube ,buffer and spring that are used in the Carbon upper configuration. I don't know about uppers.