[lurkingknight]

the hopup and inner barrel float in the outer in most guns or are attached to the gearbox but still float in the outer barrel. With no inner barrel, it's probably likely he has no hopup unit.

If you ever wish to take your silencer off, you need a shorter barrel, otherwise your inner will just stick out.

Depending what cylinder came with that gun, you could probably get a 380-400mm barrel without an issue.. but if you don't have the right cylinder ,then your fps will suffer with a longer barrel.

Up to you how you want to deal with it. I'd recommend just sticking with a 383mm barrel and run the silencer as a tacticool feature. If you really want to put a longer inner in, make sure there's enough length outside to cover it. If the barrel is too long it sticks out the end or is right at the end of the silencer and if you put it in the dirt, you'll fuck up the inner barrel good and have to clean it mid game.

6.03 is the diameter of barrel that seems to be most consistent. 6.01s do jam if they get dirty.