It is more than that. It is a direct development....something many experts on these boards claimed it was not.
I disagree.
I see it as a totally different development.
6.8 SPC merely sparked their interest ... along with 120+ years of other work in the 6.5-7.7mm caliber range. Many militaries have focused on 6.8mm as seeming to be the 'ideal' caliber, for many decades - almost since the advent of smokeless powder.
I see this new 6.8 development, in reference to 6.8 SPC, as something even more ridiculous than .308 Winchester being a "stretched .300 Savage". You can't stretch a .300 Savage to .308 Winchester. A new case must be made.
The engine in my truck can trace its roots all the way back to a small displacement V4 (yes, four cylinder, V-configuration) that was made and used in England in the 1950s.
But if you put my Illinois-made, fuel-injected, overhead cam, composite gasket, aluminum 4.0L V6 next to that cast iron, carbureted, low compression, leather gasketed, pushrod 1.2L V4, you'll instantly recognize that the inspiration for something doesn't necessarily mean that the end result will resemble the origin in any way ... other than performing a similar basic function (such as being an engine that provides rotational force, or being a cartridge that launches bullets).
The 4.0L V6 in my truck now actually has more in common with a Duesenberg straight-8 (Model A) than it does with the V2 it supposedly evolved from.
The current military 6.8 development program has, in my opinion, nothing more to do with 6.8 SPC at this point than sharing the same nominal caliber. (And I use the word 'nominal', as it's possible that they could end up with a .275" or .280" projectile and have absolutely nothing to do with 6.8 SPC by the time anything makes it to trials [if ever].)