I have bought two very nice deadblow mallets from Enco.
The mallets are very inexpensive and come in a number of sizes.These
are one piece black mallets covered in rubber or some type of
plastic.I have been using these heavily for years and they hold up
quite well. They are far less costly than through most of the major
jewelry tool suppliers. I also have one with the replaceble faces
that i like very much for certain jobs.
Hope this helps.