Originally Posted by chaz
Wait... a 4" 6.01 vs a 24" 6.08 will perform the same? or, am I using cheap crack again and reading your statement wrong?
the bore diameter doesn't have much to do with it as much as bore consistency. Over a longer barrel, the bore has higher odds of not being truly straight.
Bore diameter will contribute to fps increases in the case of tight bores because your fps will go up with a tighter bore due to higher pressure.
Barrel length has little to do with it as long as the air ratio from the charge volume is properly matched to the barrel volume. Too much air will cause turbulence at the muzzle which may disrupt the flight path.
Why people may perceive better grouping size after upgrading from brass or old barrels is corrosion, dirt, grime, bb scum, inconsistent bore diameter/straightness, and even poor air seal at the hopup unit.
Longer barrels work in real steel because of rifling, the bullet expands and is grabbed by the rifling groove and twisted in the flight path, creating gyroscopic stabilization, like a football in flight. You can't really do this with a sphere cause it's a sphere. Twisting it longitudinally will not stabilize the BB. It's more like a golf ball than a football.