Re: Amazing the amount of research and design...
The British Army has long had a preference for soldiers hitting what they shoot at. Some of it has taken on an element of myth, but even something such as the "Mad Minute" was judged by counting hits on the target rather than shots fired, and the soldier could get extra pay.
And part of why there is all the fuss about getting the ballistics the same is that it lets the soldiers keep hitting the target. You can get more penetration by increasing the velocity, but that changes the path of the bullet. And that means new sights, and makes the stocks of old ammunition less useful.
Most of the effect of the new round has to come from the difference between steel and lead when it hits armour.