The M1 Carbine is the standard by which all PDWs are measured.

[stanc]

Bottom line is that to my knowledge there has been no actual testing of something someone can present as a service ball round of Grendel to any of the issued service cartridges for accuracy, penetration, and terminal effects. The reason is simple. There is no developed round of service grade Grendel ball ammunition to compare. Nor a service grade carbine chambered for the Grendel.

Nah, that ain't the reason. The reason there has been no testing is because those (like myself) who had the interest and desire, lacked the means, while those who had the means, lacked the interest and desire.


Suitable 6.5 Grendel factory ammunition was available:


And until the demise of Sabre Defence, Alexander Arms marketed a 6.5 Grendel carbine that was identical to the M4. https://gunblast.com/65Grendel.htm