I am rebuilding a Auto 5 forearm and have a question for someone more knowledgeable than me. The forearm end that goes against the receiver has a raised ring that fits in a groove on the receiver. This raised ring is not made of the forearm wood but is a different kind of fiber. It helps reinforce the wood. It is glued or epoxied in and I am looking for replacement fiber rings. I have one for a 20ga but am working on a 12ga forearm, it is to small. Anyone know where to get these. I bought the one I have but cannot for the life of me remember where I got it. Help!