Looks like a German hunting rifle,Maybe one that was pressed into serivice by solider holding it.Foreend is typical for European hunting rifles as is the flat spoon bolt handle.I have a similar looking rifle,but is a pre WW1 type of rifle with dst,dosent have the flat bolt handle.Very interesting picture though.There is a very good book on the Mauser commercial hunting rifles from Collector grade publications.It is expensive but i think worth it for all the info on Mauser and the developement of the 98 action and the commercial varitaions.