You may want to move the scope forward before altering the stock length. Often a scope will be mounted far to close to the shooter which will cause you to back up on the stock. When you shoulder the firearm to where it's comfortable your scope is too near your face and you tend to move back with your head or reposition the stock on your shoulder. Either adjust the mounts or slide the scope in the mounts forward. You will stretch out toward the scope and this should correct your "cramped" issue.