Similar bolt treatments are encountered on early German sporters, even Model 88s. Most that I've seen were modified mil actions. This one was probably flattened for the mounted scope as stated above. Most likely when the scope was mounted, the gunsmith included the bolt treatment. Likewise, the butt extension was done after the rifle left the factory. The Brits were usually pretty good on matching the wood extension to the grain of the stock. Everything done to this rifle says German/Austrian to me. Even the engraving on the bolt knob. It appears to me to be Fritz's custom rifle done by his local gunsmith, Hans.