Grendel as a Universal Infantry Cartridge

[stanc]

So the main selling points for a new cartridge will IMO be to replace 7.62mm in portable guns for dismounted infantry while saving a substantial amount of weight, and to standardise on one calibre for such troops.

7.62mm would remain in use for a long time in vehicle mounts, but that doesn't matter since they have their own ammo supply line. 5.56mm would probably hang on in more of a PDW role in lightweight carbines in non-infantry units. But the idea is that the line infantry would only carry weapons in the new calibre.

I understand that. I'm just very skeptical about the chances of getting the US/UK/NATO to adopt another caliber that doesn't replace one of the current standard rounds. That would make for a 3-caliber system, to which I see only historical opposition.