Well ultimate accuracy form a 556/223 is really no more or different than any rifle cartridge.
it takes a lot, a LOT of work on the reloaders part to obtain that, First likely your ultimate round will not fit in you magazine so you have a single shot.
then you will need matched cases as to volume, you will need match projectiles (which are not good normally for hunting), you will need to weight every match projectile to get the best of the bunch, you will need special dies that can seat precisely and neck size only, oh yea your ammo will likely not fit another weapon either, then you will need a way of uniformly making each neck the same thickness, are you still reading??
measure each powder precisely for each round, then begin to work up loads with different powders until you find the best accuracy with each projectile!
OR just reload acceptable 556/223 ammo and have fun.
Hope this helps.
it takes a lot, a LOT of work on the reloaders part to obtain that, First likely your ultimate round will not fit in you magazine so you have a single shot.
then you will need matched cases as to volume, you will need match projectiles (which are not good normally for hunting), you will need to weight every match projectile to get the best of the bunch, you will need special dies that can seat precisely and neck size only, oh yea your ammo will likely not fit another weapon either, then you will need a way of uniformly making each neck the same thickness, are you still reading??
measure each powder precisely for each round, then begin to work up loads with different powders until you find the best accuracy with each projectile!
OR just reload acceptable 556/223 ammo and have fun.
Hope this helps.