Need advice on miniball

[Timmer]

I have an 1861 Navy Arms Springfield and I am shooting a 395 grain x .580 diameter miniball that I am casting myself using pure lead. My problem is that any powder charge over 40 grains blows the skirt on the miniball.

Can I reduce the diameter of the base pin to thinken the skirt and eliminate the blown skirt with heavier powder charges?

Anyone experiment with this idea? The rifle has a 1 in 48" twist for the rifling. The mold is a RCBS .580 mini ball mold x 415 grains that comes out .580" x 395 grains.

Thanks for your input.

[frontier gander]

how exactly do you know that you are blowing the skirt?

I cast a .500" 360gr minie and shoot up to 110gr American Pioneer and recovered the bullets and no blown skirt.

If Accuracy is poor, maybe the rifle just doesnt shoot them well.

[ResearchPress]

I'd ask the same question re. how do you know the skirt is blowing? If you have recovered bullets with blown skirts; are you sure it is the powder charge causing the problem, and not imperfections in casting.

You don't say what grade powder you are using: try an FFg grade if you are using FFFg.

The bullets quite light. My Minie bullet is 560 grains and fired in an original Enfield with 1:48 twist rifling. I shoot mine out to 800 yards.

See the following, it may help: http://www.researchpress.co.uk/firearms/british/enfield/management.htm

David

[JeffinNZ]

Even 40gr of 3Fg is far from a stout charge. Are you skirts PERFECTLY formed?

[Southron Sanders]

I have been shooting original and reproduction Rifles and Rifle Muskets using Minie Balls since 1968 in the N-SSA.

Sounds like you have a Minie Ball "skirt(s)" stuck in your breech.

Over the years I have experienced this phenonomen several times-it generally happens like this:

1. For whatever reason, a Minie Ball sheds its skirt when you fire a round. Half of the Minie Ball (the first half) flys down range. The rear half of the Minie Ball is left stuck in your breech. Usually this occurs when you shoot a round that has folds or a void in the skirt. i.e., it was not cast properly.

2. Every round that is fired thereafter leaves it skirt in the breech! Even if they were perfectly cast bullets!

3. When this condition occurs, your chance of having a "Cook Off," go way, way up! i.e., the musket discharges when you pour the powder down the barrel to reload.
(ALWAYS, ALWAYS POINT THE MUZZLE AWAY FROM YOUR BODY WHEN RELOADING AND USE ONLY TWO FINGERS ON THE RAMROD!)

4. THE FIX- have a competent gunsmith pull the breech plug and knock the skirts out of the breech. This is about the only way this problem can be corrected because you will waste a lot of time and energy trying to pull out those skirts from the muzzle with a worm.

5. I have been shooting the Hodgdon .58 Minie for a decade now and have NEVER had one lose its skirt - but then again after all my Hodgdon Minie are cast I visually inspect them. Any with folds in the skirt are thrown back into the melting pot,

6. I also weigh my Minies on an electronic scale. Any that are more than 6 grains "too light" are also thrown back into the lead pot as a "light" bullet indicates an air pocket or void in the bullet you can't see.

Let us know on this BB IF this was your problem, I have seen rifles that had a dozen skirts stuck in the breech-and a stuck skirt or skirts sounds exactly like your problem.

HOPE THIS HELPS - GOOD LUCK!

[mooman76]

Short answer to your question is yes. I have not had it done but have heard of some that do because they want to fire heavier charges. Like others have more or less poined out, 40 gr is far from a heavy charge especially for a 58. If your Minies look good before loading, you should not be having that problem. I would suspect that what SS said sounds reasonable. You could probably follow his advice or maybe try a maxi instead and see how they do.

[Timmer]

Thank you all for your suggestions. The bullets I've collected show a flare on the skirts. I may have used the wrong word in saying the skirts are blown. Flaired out is the correct term. Sometimes as much as 1/4" diameter larger than the .580". The 40 grain FFg load shoots to point of aim consistantly which out to 50 yards works for me. But like you have said that is not much of a powder charge. The 50-60 grain loads definitely flair the skirts as the recovered bullets show and the holes in the target also reflect the enlarged diameter. Again thanks for your ideas.

[mooman76]

You can have someone turn your HB pin on a lathe to make it smaller and the skirt thicker or try another mould. You might try a touch of alloy to see if it hold up better.

[Larry Gibson]

I'd try 40/1, 30/1, 20/1 and 16/1 lead tin alloys in that order. If one of those doesn't solve the problem then I'd have the HB pin turned as Mooman76 suggests.

Larry Gibson

[405]

Minie' and musket shooting for accuracy is an art to some degree. These things can have a mind of their own! 1:48 twist should be plenty to stabilize any of the shorter 58 minies. Your charge weights shouldn't be blowing out a skirt unless there is a flaw. All this has been well covered by other posters. I would think turning down the base pin would be the last resort. There could be other things at work here.

A post, maybe in another thread, brought up the idea that at least part of a hollow base minie's stability is aerodynamic. This I'd imagine applies more to minies shot thru many of the original very slow twist bores. Seems that fast twist bores with thin skirted minies may set up another set of potential problems??? If after trying other solutions like slightly harder alloy, making sure the casting is free from flaws, slightly heavier BP charge, etc., then maybe thicken the skirt by turning the base pin. BUT, simply turning down the base pin will ONLY thicken the upper part of the skirt. Seems like the edge of the skirt will have to remain as original.... at least in the type molds I'm familiar. The only exception or possiblilty would be to turn down a "step" seamless to the mold where the base pin protrudes thru, then it would thicken the skirt clear to the lower rim. If that isn't done then, I'm not sure that much will be gained by thickening only the upper skirt (the easy method) if indeed gasses are cuttng the skirt or if muzzle pressure is flaring the skirt.

Keep us posted. Minie ball ballistics is always interesing and somewhat mysterious. Info and experience sharing is always good.

[59sharps]

your expanding to .830???

[Hellgate]

Both my Lyman 575213-OS and 577611 have thick shirts and I shoot 90grs of powder (3F & 2F respectively) under them with decent accuracy as my hunting loads in a Zouave and a Musketoon.

[JeffinNZ]

I'd try 40/1, 30/1, 20/1 and 16/1 lead tin alloys in that order. If one of those doesn't solve the problem then I'd have the HB pin turned as Mooman76 suggests.

Larry Gibson

Good point Larry. I cast my .40cal Minies in 40-1 alloy and they depart my rifle, paper patched, at 1500fps over 30gr of Swiss and shoot tiny groups.

[Baron von Trollwhack]

A standard minie with 40 grains BP fired into a dirt backstop at 100 or better will typically show a pinched, like pinching the end of a straw, base.

Impact.

My Enfield ran 850 fps with 40 grains of ffg. BvT

[Southron Sanders]

OOPS! Usually "Blown Skirts" refer to the skirt section of the Minie Ball remaining in the breech when the arm is fired. This was what I assumed was the matter when I replied to your post above.

"Flared Skirts" i.e., the skirt remaining intact but "belling" out past the bore diameter occurs (in my experience) ONLY when a soft lead Minie Ball is fired with an EXCESSIVELY HEAVY powder charge.

How are you measuring your black powder? Measurement should be by "volume" and not "weight." By "black powder" I am referring REAL black powder like Goex, Wano, Swiss, Elephant, etc.

IN my experience there is no way your Hogdon Minie's skirts should be "flaring" out with any chage LESS than 76-80 grains of FFg or FFFg black powder.

Hope this helps!

Have a Great Day!

[Timmer]

For the record, I am using GEOX FFg black powder with my powder measure set at 40 grains. My powder scale shows that the powder measure is correct as it balances at 40 grains as well. The skirt measures .045 inches in thickness at the base of the slug. I compared that to my 54 cal mini ball that I use in my TC Renegade rifle. That slug measures 0.075" for the thickness. I have had no problems with the 54, 2 1/2" 5 shot groups at 100 yards from the bench using 85 grains of the same powder. The difference in thicknesses is the reason I am asking for advice. Again, would it help if I turned the plug down a few thousandths to thicken the .580 skirt? Thanks.

[405]

Well again, there's no one on the planet who can say for certain that turning down the base pin will solve the accuracy problem. Yes, you can turn it down. All the suggestions were given to see if by experimenting a little, another, easier, reversable solution would work. If turning down the pin solves the problem then great. But if it doesn't... then what? Since the periphery of the bullet is most critical for gyroscopic balance, any small difference will show. Also, some guns and some gun-bullet combos just won't shoot as well as others. I've found that minies and muskets to be very tricky for accuracy and some just aren't as accurate as other muzzleloader types. Good luck

[Timmer]

Okay, over the weekend I turned down the pin and cast up some pure lead miniballs. Today I had the opportunity to test my cast miniballs. Three shots went into 6" at 100 yards from the benchrest. I shot two and a young Airforce solder, interested in black powder firearms, shot the third one. Nice round holes with no bulges to the skirt. I used 60 grains of FFg black powder and Crisco lube. I will revisit the range and test several powder charges over 60 grains like 65, 70 and 75 grains in the near future. Thanks everyone for your suggestions and information. Enjoy shooting BP!