Actually, the Babbit tool approved for S&W 'wacking' is a bar unto itself. It is just a round bar of lead alloy about 3/4" to 7/8" in dia. and about 4" to 5" long.

Being a lead bullet caster since about the age of 18 (a looong time ago) I started seeing other possibilities for the use of lead blocks on my gunsmithing workbench. I now have two Lyman type cast ingots of lead laying on my bench at all times. The tops have various sized "V" grooves or square grooves to aid in holding a part or a gun while doing something else to that part or gun. I also have a casting of lead out of the bottom of a round bottomed melting pot laying there that I use as much as the ingots. It looks like a little low igloo of lead. It is perfect to aid in backing up a small part that is handheld while being polished, sanded, filed, etc. ..... When my lead 'helpers' get too beat up and tending to be less usable than usual, I just recast them and start over. ....