Anyone have both 600mm and 700mm .25 cal barrel?

If you have both barrels. How much fps do you gain from the 700mm vs the 600mm, with same setting and ammo and only changing the barrel. I'm guessing 30-40 fps more? Do you notice better accuracy with longer barrel? I just want to know so I can consider is it worth it to upgrade to a longer barrel.

Mod Edit: Moved to Other Parts, Accessories and Equipment forum