It's like I said earlier, the self contained projectile munition is about as good as it can get for anything smaller than heavy armor. We may someday manage to go caseless, but it won't be used, it isn't going to be something that you can equip an army with.
Projectile weapons can be made to destroy literally everything, other than ghosts. They have to have propulsion, and any form of propulsion needs acceleration, whether it's a barrel full of hot gas or a tensed bowstring. The only, yes, only practical way of pushing a projectile to high energy in a portable weapon is to self contain that munition, so that the weapon doesn't need unnecessary seals, breech improvements, guidance systems, etc.
Ammunition works in the most primitive weapons possible because that self contained cartridge and barrel, under even really nasty condition, can push the projectile out without sustaining damage.
We can use rpg rockets or mortars, or even multiple component artillery, but small arms, especially mass production items intended for hard use and neglect will probably be powder fired caused ammo.
I'm surprised that electric primers failed commercially. They work in other applications.