I did some quick research on the brass hammer. Looks like they still make them but under a different name.
Flex-Flo brass hammers last longer with greater economy and safety. They are made with a saw tooth hollow head, eliminating mushrooming. This unique head design allows it to keep it's dimensional stability, shape and balance. Cast heads are made with 85-5-5-5 brass and are pinned to genuine hickory handles. These are the old CUSTANITE brand hammers.