vr2uhu

hi guys
i have a plastic M9 bought around 3 years ago
it have a fixed hop up system which is way over..the bullet is balooned after 20 meter.
any one know if there is a variable hop system that can fit in the market ?
or where can i find a substitute for the hop up rubber?
thanks

vr2uhu

actually yes. .....i'm sure it's a fix type.
for the variable type there is a opening on the hope up rubber attaching to the bottom, need a hex to tune.........