Turning up a round (carver's?) mallet is so easy - quicker than making a traditional rectangular head and then fixing a handle, that's for sure. I just used a hardwood log from the firewood pile, turned it to the round, and turned the handle to a comfortable diameter. it's lasted about 5 years, no idea what the wood is. It has split now, so it wouldn't win any turnery competitions, and the 'hitting' surface is starting to break apart , but it still does the job, and has saved my wooden chisel handles from damage (not that I would use a hammer on them), also saved my fingers - you don't have to look at the chisel handle when striking it. Perhaps it's time now to make another one, and put the original back on the firewood pile.
K