It is generally agreed upon that a longer and tighter barrel will allow the bb to accelerate to a higher velocity with less turbulence and thus allow you to get a more accurate shot at range. However this is also dependent on other factors such as the cylinder porting and head as well as the general air seal and hop up type.
Sufficed to say, if you want to improve accuracy at range your best bet is to use a slightly heavier bb of good quality. Such as a .28
Also, don't expect accurate fire beyond 200 feet without a monumental amount of tweaking and a substantial investment.