What size ball for .41 caliber?

[ShinyPartsUp]

On a whim I went into a pawn shop and picked up an Armsport Italian-made New Orleans Derringer replica in .41 caliber. This was an impulse buy. The bore has a slight frost near the muzzle that should clean up, and some heavy but non-pitting rust in the bore way down by the nipple.

I don't know a lot about black powder, though I'm learning. What size ball and patch would be reasonable? My research shows a .395 cast ball with a heavy patch might work. I'm not sure what charge of Goex to try. Safe suggestions? I won't be shooting it a lot, but at $60 out the door I couldn't pass it up.

[Nobade]

Is this pistol rifled or smooth bored?

If rifled, try a ball bore diameter minus one thickness of the patch.

If smooth, bore diameter minus two thicknesses of the patch.

Don't take their word for it, measure it and you will know for sure. If you don't have measuring tools, a local machine shop may be able to help you out.

-Nobade

[ShinyPartsUp]

Thanks Nobade. My micrometer measures the rifled bore at .402 from groove to groove. I'm thinking either a .395 ball with patch or a slightly oversized ball and using a ball starter to get it in for a good seal. Sound like good thinking or am I off?

[Nobade]

If the grooves measure .402", what does the bore measure? .395" is probably going to be too big. You want to go bore size minus one thickness of the patch you are using as a starting place.

-Nobade

[Battis]

Does the barrel unscrew for loading? If so, it might not use a patch for the ball.

[ShinyPartsUp]

Barrel is permanently attached. I'm having a devil of a time measuring the lands for some reason. The micrometer slips a lot -- maybe my hands are a bit shaky, but the lands seem small to my eye. What I have done is bought a used (got it cheap) mold for .41 caliber round ball. I'll post an update as soon as I get firmer data.