When my grandfather passed it down to me he said it's a captured Mauser, but I don't really see any markings on it besides an R and some serial numbers
There is no way to tell if it is a bring back with out the papers.
It kinda looks like a WW1 model. I would bet that it was bought at sear in the day. My grandpa told me how they would have barrels of them in the store for 20 bucks each
looks like a spanish mauser based on the bolt shroud, this would have slightly predated the model 98, if it was a capture gun it would have had to have been captured during the spanish american war.