Single shot target pistol HELP!!

[lanedh]

Hi all:
I have a custom made underhammer target pistol acquired about 35 years ago at Friendship; never got to shoot it at the time or until now. The bore diameter is supposed to be .432"; a bunch of .431" rb and .007" linen patches came with it. The builder told me he had used a special kind of coated fabric used in aircraft; does this mean anything to anybody?

Last night I took it apart to check the condition of the bore and measure the twist. The bore has 8 grooves which seem very shallow, like a modern breechloading rifle bore, and the twist seems much slower than the customary 1:15 to 1:20 needed for pistols. The bore is very clean with no rough spots or rust. I believe the builder said the barrel came from a damaged rifle.

A couple of questions come to mind:

Should I try to use the nearly bore-diameter balls with the thin patch? I think that kind of fabric will be darn near impossible to find hereabouts. In which case, what size ball would be best to start with, using Wal-Mart .015 pillow ticking? Also a starting load for Goex FFFg?

Is the twist too slow for pistol? If so, what if anything can be done to make this a tight grouper?

Any ideas you guys can provide to get me started on the right path will be greatly appreciated. The pistol is beautifully made, has marvelous curly maple grips and forearm, and a clean crisp let-off. Needs only an adjustable rear sight and she's ready for the firing line. This girls cries, "Feed me!" :thanks:

 

[Pittsburghunter]

I would try it with the patches that came with it first. Make sure you save some incase you need them to find new material. Boy that is an interesting calibur. have you tried putting a michrometer in it to check the bore diameter yourself? will those balls you have roll freely through the barrel without a patch?

Good luck hope it is a shooter.

 

[lanedh]

Hi P'Hunter--

I pushed a ball through from the muzzle; a ball mikes .431", the rifling engraves it slightly so the bore must be less than the .432" I was told. The first inch or so below the muzzle the bore loosens up a bit altho the ball doesn't free-fall down the bore, it still needs to be pushed.

Tonight I will try to establish the actual twist rate by methods mentioned on other posts. My main concern is whether the twist will be too slow for such a short barrel, even with a low powder charge--I'll probably start at around 20-25 grains FFFg.

v/r, Dave

 

[Zonie]

The balls you have sound like they might be either Dixie #BU0406 (.430 diameter) or Dixie # LB0344 (Hornady .433 diameter swaged balls).

As for the "aircraft material" I don't know what it is. If it is pure linen it would be ok to use but it might be some modern man made material which could foul your guns bore.
Speaking of pure linen, you might see if you can find a Cloth store where they might have some. As memory serves me, it is not only tightly woven, but it is thin.

The rifleing does sound like it is too slow for a pistol, and to get sufficient spin on the ball, you might have to use rather hot loads. Only shooting will really let you know what it's doing.

Other options might be to try to find some lead pistol bullets for a 10mm (.401 dia) or a .41 cal (.410 dia) (who doesn't remember the Ruger .41 Magnum?).
The obvious problem is all of these are bullets and because of their length they need the faster twist a lot more than a ball does.

Good luck.

 

[Russ T Frizzen]

There used to be a material called Ceconite that was used to cover light aircraft at one time. It was strong and light--and man made. Perhaps that is the material in question. I'd sooner eat road apples as put it down one of my barrels. Linen is good, and pillow ticking. I guess silk would be fine, too, but I doubt it would give you much extra range. But then again, Nathaniel could be right.

 

[pappydean]

Hi Bluejacket,
If the twist in fact proves to be to slow, you could ream it out for a smoothbore. Would still be a great pistol. :imo:
pappydean

 

[arcticap]

The thinnest standard OxYoke patches are .005 which if used with the balls you mention would give you +.004 of material to fill the rifling grooves. Sounds like it would be the patch to start with as long as the patches stay intact upon loading and firing, which proper lubing should assist you with. :m2c:

 

[lanedh]

Thanks to all you guys for your inputs, you've given me a lot to ponder.
I will start looking for more thin linen, but if that fails then the .005 Ox-Yoke patching might fill the bill. I'll try to keep you abreast of my progress. Thanks again.

 

[Zonie]

If you find the .005 Ox-Yolk patches, you might want to buy a bunch of them.
Ox-Yolk is out of business now. :boohoo: