My 1903 M/S in 6.5X54 M/S had such a dovetail cut in it and some previous owner had removed the scope mount and plugged the dovetail with a nicely fitted insert, which I decided to conceal with a Redfield style mount. Neither your 9.5 nor my 6.5 is a very intense cartridge compared to more modern ones and with loads comparable to factory loadings I am not concerned about the strength of the receiver ring. I also have more than one Mauser factory sporter with similar dovetail cuts, presumably made at the factory.