To use this table:
1:Measure the distance between the inside of the gun muzzle to the front of the trigger in millimeters. This is the "gun length".
2: Select the rubber diameter you are using. "Short" will give maximum power.
3: The measurement where "gun length" and "rubber diameter" interesect is the length of rubber you need.
If using double rubbers select your gun length but use the next largest diameter for the length of each rubber.