Hey everyone. I need help identifying this Mauser. It has absolutely no markings other than what appears to be a faint letter R on the top of the receiver. All the other markings appear to have been ground off. None of the serial numbers match. I'm guessing it was sporterized later in life. The action is cock on close and there is a gas escape port on the left side of the receiver. There is also a flat indentation on the underside of the bolt body. Anyone know what this is and what caliber it takes? Thank you in advance.