I have two 870 express shotty's that both had the same problem....upon shell ejection they stovepipe so the shell never gets fully ejected from the reciever. I have sent one back to Remington but is there a way I can just sand down the ejection port on the reciever allowing more room for ejection? Will this solve my problem and how should I go about it? Grit on sandpaper? Where to sand? etc. thanks