[DarkAngel]

Think about it this way. a cylinder gets its strength from the even distribution of force applied to the whole surface, If you cut a small portion of it to disturb that even distribution, it completely loses its ability to distribute that force, causing the shape to collapse. The same is true for Hop up Rubbers.

While depending on where and how you cut it may compromise it to different degrees, it still will affect it in some way. IE, not enough surface friction, causing the nozzle end to stretch over and pull over the IB, Pieces getting caught during installation due to unstretched pieces snagging etc.