I obviously have much to learn, I assume thats the button sticking out of the rear of the bolt (I did notice it stuck out farther than my Kar 98 sporter I just purchased), I`m not sure if Mr. Hansen built the rifle or just the box, I bought it consignment at my favorite gun store. This one has a hinged drop box magazine unlike my Kar 98, that your put a bullet in to pop open then you get a handful of shells and a mag plate and spring, I sure like the hinged floor plate better

(Did I mention I`m new at the Mauser stuff...)