Guardsman26 said:

The velocity could easily be increased to 1,000 mps for better body armour defeat in a standard brass cartridge. 

I'm skeptical of that.

These were the Quickload specs I had done awhile back. These were with a lead core bullet; I suspect velocity would be a bit lower with a EPR due to reduced case volume from the longer projectile. 

6.5C 123gr@ 62kpsi

16”- 2795fps / 852m/s

20”- 2962fps / 902m/s

6.5C 123gr @ 75kpsi

16" 2960 fps / 902m/s

20" 3124 fps / 952m/s

6.5C 123gr @ 100kpsi

16" 3128 fps / 952m/s

20" 3279 fps / 999m/s

Mr. T (MrT4) said:

Actually I am a bit surprised that 6.5 Creedmoor was chosen over .260 Rem , a design that is far better suited for automatic weapons and also has a bit more boiler room and can push bullets to higher speeds

6.5C was chosen as it had more Ogive space for use with heavier weight projectiles / experimental future projectiles:

https://soldiersystems.net/2018/03/23/ussocom-adopts-6-5-cm/

That's fitting considering neckless looks more and more viable (even brass case because of our man emeric) so of course we'd pick one with more ogive space right as more ogive space stops being a problem.

Yup, that sounds about right...

I cannot even at this point.