[Hectic]

No im saying in the link i provided when it says s cylender is for xxx-xxx length barrel the longer barrel is making maximum use of the cylender and the shorter one is not so its less efficient.
So for a cylender with a 4/5 port a 460mm barrel uses all the volume and a 364 is wasting some (you will have lower fps and harder impact of piston to cylender head because the bb has exited the barrel befor the piston completes its cycle thus wasting air energy and lowering fps)
A vsr 10 is optimal for 500mm inne. A gspec has a 330 mm inner and with all the parts the same for a 500 fps build the 330 mm barrel will reduce fps by 100 as the inner barrel increases in length or the cylender port is moved forward (shortening the cylender) the fps increases
So if space allows in your gun (outer barrel length silencer ect) your beter to use closer to the maximum length that the cylender can support