Originally Posted by shemoves
What would be considered tight grouping? 1MOA?
all depends on what you are shooting, and AR yeah 1 moa is good... in a bolt gun... the rifles that we make in school shoot sub 1/2 moa at the biggest... if they are shooting bigger than that you did something wrong...
as for the whole yaw and fragmentation thing... again in fast twist bbls bullets won't yaw, the only bbl twist rate in an ar that has ever produced an actual yawing effect on bullet impact was the original 1:15 twist, this was unable to produce accurate grouping in extremely cold(dense) air, what you see in ballistics gel is the bullet torquing off its center line... ITS SPINNING... remember playing with tops as a kid... spin one and then poke it or watch as it slows down same concept, it becomes unstable and spins off in the direction it was spinning as it slows down. the main difference is a bullet is slowing down to nearly a stop almost instantly.
fragmentation is a whole nother kettle of fish. You want a bullet to expand and fragment upon impact and deliver as near to 100% of its energy into a target. thinner jacketed bullets such as a matchking will expand and actually tend to basically explode when they hit soft tissue (hence why most police snipers use federal match gold ammo) a heavier denser constructed bullet will most likely pass through a target and not deliver all of its energy. it will poke a hole in, cause some initial hydro-static shock (water is non compressible) but the bullet will continue on its merry way out of the target. this is not a good thing. the reason a lot of hunters want a heavy and strong bullet is because they want a blood trail that they can track, two bleeding holes is better than one thought process.