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.
Note:
If using double rubbers select your gun length but use the next largest diameter for the length of each rubber.