C8A4 was to be an interim fix, CMAR was pushed up from its original date of 2032, CAMR is a brand new rifle and carbine. Both are short barrels so carbine drill will still apply. GS is about 12.5" barrel, and the FS is a 16" IIRC. CMAR designated C25, is a modern full modular rifle platform that brings us up to modern NATO standards for a service rifle. While at its core it still looks like an AR, the internals, and design have been drastically changed over the C7, the FS varient for the infantry will have a stronger optic, option for a suppressor and an optional TWS