As I recall one of the very early features of MST tech was the ability to fire three rounds (of whatever) before recoil due to the speed of ignition.
One of the first research grants was to develop a sniper rifle based on this tech - which had issues related to the seals from memory - I wonder if such a project would now be successful?
This "triple tap" could be the basis of the hyper carbine concept?
Just some throw away thoughts .....