Advantage to Long barrels + Big cylinders?

I can confirm that a longer barrel will give you more fps, because the bb has longer to accelerate. As for making it quieter, most of the sound comes out of the receiver section and echoes in the stock, not the barrel. A longer barrel if anything will just add a few more vibrations to hear, though you probably won't be able to notice it. (Pretend this is a new pararaph lol.) Barrel size past a certain point will not increase accuracy.With a properly tuned hop, you will see no difference between the accuracy of a g-spec vsr and the pro version. The only thing the longer barrel of the pro version does is add some LRB freedom. Of course a barrel does stabilize the hop somewhat, like with an LRB, but having an uber long barrel can only hinder mobility. People use bore-up parts because they are either obsessed with fps or have the misconception it will give a more stable hopup somehow. Realistically, if you already have that bb going straight and you already applied hopup to it, more barrel to keep the bb centered won't accomplish anything. I think there is a stickied post about this somewhere but I don't feel like searching through posts.

@Chach- With all those free fps mods out there (there is even a whole big write up on them stickied somewhere) it really isn't worth it. Just get a batter spring if you really want that extra kick which serves no purpose either. Past a certain point, fps does nothing for accuracy (assuming hopup stays consistent). You'd just be throwing money at your rifle to get slightly more fps out of it. Forgetting about the caps, it won't do you much good anyway. The only thing that affects accuracy is the hopup. You can whack the bb with a baseball bat and it will go straight, but that backspin is what keeps it level, and keeps it steady in the wind. (New paragraph.) @Sand- for the most part, the mainstream rifles already have optimized volumes. It also depends on fps though, as mentioned in the sticky two from the bottom, labeled something along the lines of "the airsoft trajectory project" or something. The post also tells you how to find the optimized volumes, or at least a generalization of them. Sorry for the long posts, lots of info.