So I recently purchased a Marlin 336 30-30 rifle and while cleaning NEAR the buttstock a small, circular black piece with a small hole in it fell out. Looks like a washer or something but with a smaller hole. I have no idea where it fell from and my gun is broken without it. I put all the other parts together and without the circular piece the rifle won't load more than one bullet, if fact it gets stuck. Can anyone help me and tell me where this part could go?