that is the best pic I have; what you are looking at is a little pad. it has 4 rounded , clear, hard rubber bumps on it, that are shaped like an Igloo. They peal off the paper backing. you can find these at any home improvement store, or hardware store. these are small , for cabinet doors, and they can very in hardness, and size, up to black soft rubbery ones, to stick on the backs of doors, so they don't slam into walls. go for the smallest hardest ones you can get, as they will be less prone to absorb water, or change shape because of temp changes. stick them on the end of your stock, between the stock and bbl. you will only need one. You may find it interesting, to shoot a group, them move it say 1/4 inch at a time, back towards the receiver, and see if you get a better group or worse group.