As Topgun mentioned a bead works great as long as you make sure to get down on the stock. I had a few issues once and got a ghost ring which clamped on the rib of my SBE and a fiber optic bead for the front. The ring is about as large as a small pea and is like a peep sight with a couple of fiber dots on the side. With my older eyes I put the fiber bead on the head and neck of the turkey and my eye naturally looks through the ring and centers. Works great and doesn't weigh anything.