Okay so this may sound dumb, but I feel the need to muse a little bit, hopefully get some suggestions on better ideas/alternatives. So tomorrow or Thursday, a 308 Ruger American predator should be getting to an LGS for me to buy, it's gonna be a little over $400 after tax I believe, like...

So someone who owed me some money couldn't pay and I took this bolt action rifle as a form of payment. There are no markings, stamps, serial numbers, it has what looks to be a 5 or 7 round mag, but I have no idea what caliber it fires. Please help!