This is a receiver from a 1939 Model 70 rifle H&H magnum rifle (.300 H&H or .375 H&H), stamped with the serial number 18579. This receiver has had a series of holes drilled along the left side in order to accommodate a side-mount scope base. Some of the holes have been filled, or partially filled, and the bluing has been removed from that side of the receiver.
NOTE: Laws governing transfer of firearms require that receivers be shipped to an FFL holder. If you do not hold an FFL or C&R license, you will need to enlist the services of an FFL to complete the transfer. If needed, we are happy to assist you in locating an FFL holder near you who can complete the transfer on your end.