1842 US rifled musket

[varsity07840]

Most of my shooting with my original rifled '42
has been with the Rapine minie.
I don't know about Armi's version, but the originals had progressive depth rifling, tapering deep to shallow from the breech end. If that's the case with the repro, then an lubed 14 ga.
shotgun cusion wad may help. A patch/ball combo that is tight at the bore will not be so at the breech. The wad will give you a better seal. I've found that while card wads will provide a good seal, they can be a pain to seat in a fouled bore, especially if you're using ones that are wide enough to fill the grooves. At least thats what I found with my limited PRB shooting out of my 3 bander. Also, I'd try cutting the patches at the muzzle. Bob Hoyt is doing a lining/rifling job on an original smoothbore '42 that was cut down to 26". Someone tried making it into a musketoon. I'm going to do some serious experimenting with PRBs in that one.
I'll post results down the road.

Duane

 

[bingo1952]

Ditto! Just because it has a slow twist doesn't make it a round ball shooter. Minie balls are a semi weight-forward projectile. Not so much as is a shotgun slug but enough that a slow twist barrel (what most think of as a round ball twist) will still stabilize the bullet.

 

[nkbj]

That's the strange part about this pattern rifling in this large a diameter.
When you short start the ball, the linear dimension of the patch circle where the ball diameter is at tangent to the bore is 1.23" greater than that of the bore perimeter. That 1.23" of "extra" material has to go somewhere. With this pattern of rifling it doesn't go somewhere evenly due to the three way stretching action on the 90 degree warp and woof of the fabric. I had to recover a bunch of patches before I cottoned on to this. Reminds me of Engineer Scott's comment about over taking the plumbing.
If I had a roundball pattern of rifling it would be staked at each of several grooves in a more even fashion. So, I'm gonna try to out wit it. By the way, the bore diameter is a real 69.

The shallow, three groove rifling in a rifled musket like the M1842, reproduction or original, is/was designed to work with a Minié ball, why try to force it to work with something else? Patched round ball works better with deeper grooved rifling. Oh, and mine measures .685 like most other repop ".69".

Yes, shallow three groove rifling does not always work well with round ball. But, to answer the question, it's a muzzleloader, now with a very accurate round ball load, and that makes me a happy guy.

 

[nkbj]

You've got me confused a bit.

By saying it is 1.23 inches larger than the bore perimeter are you saying the bore perimeter is 2.167 inches and the amount of material that is contacting the bore is 2.167 inches (.69 times Pi) + 1.230 inches making the total length of the contact length 3.397 ? If you are, then I must agree with you. Something is very strange.

According to my calculations the diameter of the contact circle for a .69 caliber bore (rifled or unrifled) would be about 1.084 inches, that being equal to 1/2 of the circumference of the roundball.

The proper patch diameter (or the size of a square if you like square patches) would be 1/2 of the ball circumference plus one ball diameter or, 1.77 inches.

Using a patch of this size in theory would locate the patch edge flush with the muzzle when the ball and patch had been seated so that the top tangent point of the ball was flush with the muzzle.

Maybe I'm missing something?

OK, this is how it works...
Pi x bore diameter = approx 2.168" circumference.
The diameter on a cloth patch where it is tangent to the bore is 1/2 of this 2.168" circumference. The circumference of that 1.084" circle is approx 3.405". The difference is the length of cloth that has to get gathered up somewhere when seating the ball, about 1.23".
Glad to report that I finally realized this thing is a rifled shotgun, started using fiber wads and am now shooting one hole groups. Yippee!!

 

[varsity07840]

You've got me confused a bit.

By saying it is 1.23 inches larger than the bore perimeter are you saying the bore perimeter is 2.167 inches and the amount of material that is contacting the bore is 2.167 inches (.69 times Pi) + 1.230 inches making the total length of the contact length 3.397 ? If you are, then I must agree with you. Something is very strange.

According to my calculations the diameter of the contact circle for a .69 caliber bore (rifled or unrifled) would be about 1.084 inches, that being equal to 1/2 of the circumference of the roundball.

The proper patch diameter (or the size of a square if you like square patches) would be 1/2 of the ball circumference plus one ball diameter or, 1.77 inches.

Using a patch of this size in theory would locate the patch edge flush with the muzzle when the ball and patch had been seated so that the top tangent point of the ball was flush with the muzzle.

Maybe I'm missing something?

OK, this is how it works...
Pi x bore diameter = approx 2.168" circumference.
The diameter on a cloth patch where it is tangent to the bore is 1/2 of this 2.168" circumference. The circumference of that 1.084" circle is approx 3.405". The difference is the length of cloth that has to get gathered up somewhere when seating the ball, about 1.23".
Glad to report that I finally realized this thing is a rifled shotgun, started using fiber wads and am now shooting one hole groups. Yippee!!

Good to hear!! What load did you finally come up with that did the trick?

Duane

 

[nkbj]

Tried using a 14 gage fiber wad under a relatively large ball and very thin patch. And, by accident I learned that this combo works only when the wad is soundly wacked into place and then the ball is wacked into place. Got humbled and then lucky. Now I wanta get meat.

 

[varsity07840]

Tried using a 14 gage fiber wad under a relatively large ball and very thin patch. And, by accident I learned that this combo works only when the wad is soundly wacked into place and then the ball is wacked into place. Got humbled and then lucky. Now I wanta get meat.

Hard seating pressure on the ball and wad probably
make the wad fill out into the grooves for a tight seal, just like a the skirt on a minie. Alot of minie shooters do the same thing, especially for the first shot out of a clean bore, to ensure a good fit and no creep down the bore.

Duane