These are bullets propelled by internal rocket motors and much lighter barrels will work because the gas pressure is lower when fired.
Also note that guided bullets have been demonstrated multiple times, it would be accurate to say they are present tech and no further advancements are needed to develop them. Militaries are just slow and inefficient and not always eager to adopt better technology, there has to be budget allocated, it has to be something a given military branch feels they have a compelling need for, and then a multi year process to select a vendor.
Regarding sniper drones: carrying around a long heavy barrel weighs down the drone/forces it to be bigger and more expensive.
So bring back 1960s gyrojet ammo : https://en.m.wikipedia.org/wiki/Gyrojet
These are bullets propelled by internal rocket motors and much lighter barrels will work because the gas pressure is lower when fired.
Also note that guided bullets have been demonstrated multiple times, it would be accurate to say they are present tech and no further advancements are needed to develop them. Militaries are just slow and inefficient and not always eager to adopt better technology, there has to be budget allocated, it has to be something a given military branch feels they have a compelling need for, and then a multi year process to select a vendor.
See https://www.darpa.mil/news-events/2015-04-27