Frank, my gun has the shim's that fit between the stock and THE reciever, but I've never tried changing them. You might have a good point there depending on how your gun fits your length of pull and shoulder. I'm happy with the sights I use for turkey hunting even though my 74 year old turkey hunting buddy gives me a hard time about them. He tells me that a turkey gun needs only 3 things and that's-------- BOOM! BOOM! AND BOOM!