For best accuracy keep ur barrel sqeuky clean. One lil bitty piece of anything can change the trajectory in so many ways. Now as far as barrel wieght is prefernce but barrel lenght has to do with accuracy. Depends on what ur using it for. All together it's prefernce to what u like. There are metals that are smoother than others an that would help. I'm waiting for a chrome lined inner barrel. That would be nice.
performance is necessary, glamour is secondary