The barrel seal activator is designed for use on the Model 11-87 12-gauge Super Magnum shotgun to improve performance when using light 2-3/4" loads. With heavy loads there is more than enough gas to properly function the Model 1187 Super Magnum. Leaving the Barrel Seal Activator on the gun with 3" and 3 1/2" loads unnecessarily speeds up the action. When the gun is operating too fast, this could result in timing related malfunctions, such as: not allowing the action to completely lock open after the last round is ejected or a failure to feed the next round from the magazine. Additionally, this could result in premature wear on the receiver which would be a very expensive repair.