Now you have hit the jackpot. It would have been a great little rifle in 6.5x57 but maybe limited a little if it had actually been regulated for the 123gn bullet but to find it is in 7x57R and will shoot the 177gn tug takes it up to being a all round stunner.You would have to be even more pleased with it now.
Are the barrels not marked with the chambering to have had it mistaken for a 6.5x57??

Von Gruff.