Minie Tumbling From Pedersoli 1861 Springfield

[Tom Compton]

Which minie was being used has been left out of the discussion. Some have thick skirts, some thin. Some have very short skirts, some longer. They do not behave the same.

X2

Also the diameter of the bore and minie. Another post mentions the musket in question has a .584 bore. NO .575 minie is going to shoot well.

Another mentions 60 gr of powder to expand the skirt.

Using a Brit made Parker Hale, 40 gr FFg and a thin skirted 550 gr minie sized to .577 I've seen no key holing. Matching bullet fit and powder charge is very much like a PRB, too loose a fit and an incorrect powder charge is a poor combination for stabilization and therefore accuracy.
TC

 

[Eterry]

My Italian musketoon won't shoot .575 minis worth a tinkers damn, but the Lee website tells how to shim the mold with greased paper, and says you can get up to .005 or more. If you Google beageling a mold you'll see how it's done. Mine now cast at .578, and accuracy much improved.

Eterry

 

[nkbj]

Erik can make it fit!
http://www.hollowpointmold.com/band-modifications/

Makes new plugs too.

 

[Eterry]

I'm sure he does fine work, and by the look of his website he certainly has the experience to modify any mold.
But it took me about ten minutes to shim my mold with lubed paper, and the cost was Zero.
Plus if I ever do get a .577 mold I can remove the paper and sell the mold as unmodified.
Of course, for best accuracy one should run the mini thru a sizer so the mini is more concentric.
Maybe I should build a sizing die... :hmm:

Eterry

Ps. I noticed my group size shrunk dramatically when I started applying more pressure to the mini after seating it. Some suggested using a bathroom scale to get a consistent weight. I don't hammer the mini after seating, but try to apply a consistent amount of force.

Et

 

[Billnpatti]

Okay, I am just wondering and musing out loud :hmm: Could it be possible that when you apply sugnificant pressure when seating a minie ball that what you are doing is starting the skirt to expand so that it engages the rifling sooner upon firing? :idunno: Or could it be the compression of the powder that makes the difference. :hmm: :idunno: I wish I knew a way to come up with the answer. Oh well, I have posed the question and that is a start. I'll have to let someone smarter than me figure out how to answer it :hatsoff:

 

[Tom Compton]

Okay, I am just wondering and musing out loud :hmm: Could it be possible that when you apply sugnificant pressure when seating a minie ball that what you are doing is starting the skirt to expand so that it engages the rifling sooner upon firing? :idunno: Or could it be the compression of the powder that makes the difference. :hmm: :idunno: I wish I knew a way to come up with the answer. Oh well, I have posed the question and that is a start. I'll have to let someone smarter than me figure out how to answer it :hatsoff:

IMO Bill both occur. A friend patented a ramrod years ago to measure seating pressure specifically as applied to PRB. Coupled with shooting over a chronograph he found a direct correlation.

At the TMLRA matches last week we discussed both powder burn rate and skirt expansion due to load compression. Several there with much more musket experience than me and the consensus was both velocity and skirt expansion occurred with increased compression.

As usual sir you are on the right path.
:thumbsup:
TC

 

[Eterry]

I lube the cavity of the mini, based on the research of Lyman which shows better performance when you lube both grooves and cavity.
The lube filed cavity may partially expand under hydraulic pressure when compressed, but I'm not certain.
I freely admit I am no expert in the use of the mini, and have only tried the high pressure loading twice.
Maybe some of our competitors will chime in here.

Eterry

 

[azmntman]

Okay, I am just wondering and musing out loud :hmm: Could it be possible that when you apply sugnificant pressure when seating a minie ball that what you are doing is starting the skirt to expand so that it engages the rifling sooner upon firing? :idunno: Or could it be the compression of the powder that makes the difference. :hmm: :idunno: I wish I knew a way to come up with the answer. Oh well, I have posed the question and that is a start. I'll have to let someone smarter than me figure out how to answer it :hatsoff:

Well he will probably do so, he is "active" again! :rotf:

I would think the pressure would not help enough to measure by the naked eye but of course one should try for equal everything when loading any BP arm :idunno: