Why didn't they just convert them to the .308 Win?? If the SPC needs a new barrel and bolt, why not just throw a new mag in there and use a real round. I also think the .223 is doing the job most of the time, its just like deer hunting, bullet placement is key.

thats already been done its called the AR-10 but in order for a 308 to be used on the AR platform everything had to be changed the reciever especially the mag well had to made larger to accomodate the larger round the 308 simply just will not fit the current AR-15/16 platform.

Yeah I knew about the AR-10, but I didn't know that they had to change that many other parts. Oh well I thought I had a good idea.

I believe the 2800 FPS MV given for the 6.8 may bewith a sporting-length, like 22" or even 24", barrel, NOT the short one on the military rifles. The figure of 2625 FPS sounds more realistic for the military weapons.