Are you looking for "Ball BLOCKS"?? Or Loading blocks??? There is a difference.
The Ball block is designed to hold a Patched Round Ball is a small block that can be carried into the field, hung around your neck, or carried in your hunting pouch.
A Loading block is the kind of thing usually associated with Cartridge reloading, and holds the empty casings and finished cartridges during the loading process, when a single stage press is used. Similar blocks are made and used by folks shooting paper cartridges, and paper patched bullets in their MLers.
There is a chart up under " member Resources" on the index page to this forum, that will give you the correct drill bit sizes for most popular calibers and gauges.
Just remember that as the caliber sizes goes UP, so does the weight of the ball. Carry only what you reasonably expect to need on a hunt. It is often better to have to Ball Blocks, one in the pouch, and the other around your neck.
The one in the pouch is back up, but usually is not needed, unless you are either having a Very GOOD DAY, or a Very Bad Day hunting. :hmm: ( You can run short of ammo two ways. Either you are shooting and hitting everything you aim at, or you are missing everything, and there is still daylight left for you to try to come home with something!)