Maybe it's a dead rat. I am not inclined to shoot something that rough.
call it a well used well abused grey rat. If only it could talk and tell us what it did for its first 100 years , how many ranches it visited ,how moch game did it bring down ,
, was it left out in the weather or in the barn wet ? did it become a truck gun ?
I have a 38-55 TD ser no 70xxx not as bad as yours, came out of cattle country a well used tool.