spare parts pistol

[Jim in Wisconsin]

A few years ago, I made a single shot pistol using a L-R mule ear lock and a 9 inch piece of cut-off 36 caliber 13/16 rifle barrel. I carved a stock of cherry wood and had enough other stuff laying around to make a sort of chunky looking pistol. It works great and doesn't even look so bad, but the accuracy is not so good. Resting it at 35 - 40 yards I'm lucky to keep them all on a large piece of paper. I think the trouble is that barrel has a 1-48 inch twist, which is too slow for a pistol. I'm using .350 balls with a ticking patch, the same as I use on the 36 rifle - which shoots with nice accuracy.
Any good ideas (besides throwing it in the pond)?

[Hank in WV]

How much powder are you using? Maybe try decreasing it a bit.

[Jim in Wisconsin]

I've used 20 grains of black powder and up to 30.  20 seemed sort of anemic, 25 had a nice crack to it.

[PetahW]

.

If you've already played around with patch thickness, and/or the muzzle end of the barrel is where you cut it, I'd re-crown it. 

[Jim in Wisconsin]

The muzzle end has been cut, but I have a lathe and turned a nice (at least nice looking) crown and carefully de-burred it. When I find a patch on the ground, it's not cut or burned, in fact they could probably be used again.
Most pistol barrels have a much faster twist than 1-48, with this the ball would make less than 1/4 of a revolution before leaving the barrel. If I could find a 13/16 fast twist barrel in 36 - 40 cal. I would replace this one to try it, but pistol barrels seem to be in short supply now.
I would love to have a Pedersoli Cook underhammer target pistol - but........

[waksupi]

I would keep increasing the load, to try to match the velocity to the twist.

[Bigsmoke]

I would keep increasing the load, to try to match the velocity to the twist.

That's what I am thinking as well.
I would start at 30 grains of Fffg and shoot 5 shots from a good rest.  Then 5 more shots at 35 grains.  Then 5 more at 40 grains, etc.
At some point your group will stop decreasing and start to increase.  Then you can experiment with different thicknesses of patching, lubes, ball size, etc. 
Only change one thing at a time and don't worry about where it is hitting until you have all the variables ironed out.  Then adjust your sights.
OR
You could send the barrel to someone like Bobby Hoyt and have him rebore the barrel and cut more pistol friendly rifling in it.  From a .36 cal, you would probably need to go up to a .45 to accomplish that.
John (Bigsmoke)

[Jim in Wisconsin]

Rice Barrels shows a 13/16 36cal pistol barrel on their site, and I emailed them about it a few days ago. So far no answer - maybe they don't use emails much?