Very naive question, but given the problem with the 7.62 ammunition is size & weight, can it be made smaller & lighter?
Whatever happened to caseless ammunition? I remember that being the future once.
If you’re of the correct era you may also remember the mocked-up photos of futuristic soldiers from the unimaginably distant year 2000 with their visored helmets (with integrated head-up display and night-vision!) clutching the ever present Heckler & Koch G11 rifle.