The round ball is definitely an enigma.

Marrkai's results I'm afraid w/ lead or even steel tho I've never used steel are probably about the best most guys can hope for.

I got 4 1/2 inches at 20 using a 5/8" drill bit, a hand drill and a block of wood for a mold. Just winged it, no special attempt made to really get the mold depth the same.

From an old thread:

"Made up a few of Daryl's wooden mould slugs. Didn't make much effort, just ran a 5/8" bit in and loaded them up.

After the first batch was too heavy, I guessed at a shallower hole and got it pretty well with the slugs averaging a little under 1 ounce. I separated the heaviest for a 3-shot group from standing up at 20 paces. Results as follows.

Group is 4 1/2 inches so not great but the barrel has no sights, sporting only a brass screw I thread into it when I cut it from 30" down to 26. So yes, it's cylinder bored. Didn't want to risk a choke on one of these wheelweights going thru at an angle.

Anyway, the shots were not wild as they indicated an actual grouping which I found interesting. I have a setup on one of my anvil stumps I use to zero shotguns, bending the barrels to address POI issues. But the barrel shoot shot pretty much on so I didn't monkey with it.

I backed up the target with a 5 gallon bucket of water but that didn't stop the slug.

First attempt on left. They must go somewhere around 2 ounces. The idea came to mind that a guy could pour one long deep hole and then cut the slugs to length for more accurate weights but I don't have a dipper big enough."

And the group:

This RB thing is something I'd like to pursue.

For truly WILD shots on or more likely OFF the paper, try one or two .600 round balls in the 12 bore. Those things make Kipling's Martini tossing "arf of yer bullets goin' wide in the ditch" a benchrest champion.

At any rate, back to centering RB's.

These here came to mind, what we call "finishing washers" and they come in steel or aluminum or bronze. My have some potential for preventing gas blowby and eliminating what the old timers called "windage".