There's been an awful lot written lately about the need for a new cartridge to replace the puny 5.56mm currently issued to NATO forces. While this round does leave much to be desired those opining that a return to the big 7.62mm is required are missing one vital point: while it's all very to say that needing to take 2 or 3 hits to incapacitate a target negates the advantage of the small 5.56mm because a 7.62mm can do the job with just one shot, not every shot is aimed at an enemy combatant.
The basic tactic employed by the infantryman is fire and manoeuvre- firing towards the enemy to keep their heads down while your buddy advances. In this situation the superior stopping power of the 7.62mm is a rendered useless- and you need a lot of ammo to do this. I can remember the first time my troop practised this action and I was surprised by how quickly we burned through our ammo. Even taking your time and firing maybe three rounds each "hop" only allows you ten moves before you need to reload. And you may be advancing to one target to engage a large number of enemy before moving on to another target, not knowing when you can get a re-supply to replenish the ammo you can carry on your person. The more ammo you can carry the better.
The HK G11, with its small caseless round, offered the soldier the ability to carry an awful lot more ammo than normal- with one 50 round magazine loaded and two more carried on the weapon itself. However, I suspect that the terminal ballistics of this round were not superior to the 5.56mm. Given what's available today, the best option would seem to be a round similar in size and weight to the 5.56mm but with better stopping power. Once again, the 6.8mm SPC seems to fit the bill.