Here's what matters
consistency of the bore (not size)
parallelism of the barrel (not length)
quality of your hop rubber
compression of your mechbox and the seal between air nozzle and hop rubber
And having the proper weight BB for your FPS
Accuracy and range is about having laminar, and constant pressure airflow behind the BB. And making sure that BB is at it's nominal relative velocity.
A 350fps gun with good seal will outrange a 470fps gun with a poor seal
And a .3g BB will have more accuracy at 430fps than it will at 470fps
Barrel length makes incredibly little difference to range and accuracy. I've had a stock 6.08 brass barrel P.O.S. HFC beretta that could hit a torso at 200 feet.
My VSR has a 430mm barrel and it'll hit things accurately out to 260ft
And most importantly, friend of mine had a 650mm barrel in their VSR and actually was less accurate than I, due to running .3g BBs at too high velocity
In theory a longer barrel always gives you better accuracy. In truth, the BB is stabilized after just 80mm in most gas guns, much more in AEGs (due to less initial pressure).
I do agree that a tighter bore decreases the BB's ability to bounce due to creating a higher pressure zone around it, to better center the BB down the barrel. But you're thinking like an engineer, that theory only works in labs.
In the real world, barrels get soiled, sometimes very quickly. Larger bore means less chance of the BB hitting dirt down the barrel.
Remember guys, science is supposed to explain what happens in the field, not to argue against it.
Gas pistols (Like marui socom) get some pretty impressive range and accuracy for having 80mm barrels and at only 300fps.
My VSR at 430mm 6.03 bore will match any accuracy you can get out of a 650mm 6.01 barrel.
I don't know the details on the science, I just know how it works in the field.