the thing about twist rates as explained to me by DevL is that if you have a twist rate that is too slow, you will have really bad accuracy. you will have the greatest accuracy if your twist rate is just barely fast enough to keep your bullet stabilized. however, it is best not to be TOO close, because changes in temperature etc could cause you to cross that line. by using bullets of lower grain, you will sacrifice a very small amount of accuracy. a 1/8 twist is relatively fast and therefore will allow you to shoot a wide variety...so you can still shoot standard 55gr with accuracy, but you can also use the heavier 75gr if you want for some specific purposes, like slightly longer range shooting or something.