If it's the gyro gain that is causing it. Make sure that all of the connections on the linkage is tight and that there is no play, make sure your bearings are spinning free, and make sure your tail blades are not too tight. They should be tight enough to not fall under their own weight. They should have enough force to hold themselves but require a slight bit of force to bend over.
If all of that is okay, then yes, lower the gyro gain two clicks and try again.