I'm hesitant to recommend slip on pads and sissy pads which exasperate the LOP problem, on a gun that is probably already too long. LOPs that are too long increase felt recoil, so the first thing to address is getting the gun to fit you and ensure it's fitted with a good quality pad. Once the gun conforms to you, rather than the other way around, you will immediately notice an improvement. Then comes the question of technique, and I'm surprised how many experienced shooters get this wrong. Start with your feet about shoulder width apart, now take a half step forward with the leg on your support side. Push the gun out in front of you, to ensure the butt will not catch on clothing as you raise it, then pull the butt into the pocket of your shoulder. At the same time flex your forward knee slightly, and shift your weight towards it, maybe 60% forward 40% rearward. Your knee can be as far forward as the toe of your boot, but no further. Obtain a good cheek weld, acquire your sight picture, and make the shot. If your position is correct, the recoil will flow across your chest, and down your rearward leg. The recoil will feel moderate and controllable, and if you are shooting a pump, cycling the slide will be very fast, as the recoil will assist the movement. If you shoot with a high elbow, the pocket of your shoulder will be open, which is good for the correct placement of of a gun butt, but if you find the recoil is still uncomfortable, lowering your elbow will close the pocket, and provide a bit of additional cushioning. Just watch that the gun butt does not rise out of your shoulder, reducing the surface contact it has with your shoulder. As the season gets later, heavier clothing will be worn, and for the most part this too will help reduce the amount of felt recoil, but heavier clothing will also exasperate the problem of too long a LOP. Additionally, you should beware of the problem of bulky materials which create an airspace between the butt of your gun and your shoulder, there's nothing like giving your gun a running start before it hits you.