Muzzleldrs Ammo Mississippi Rifle .. sizing a minie for it

Cannonman1

Private
Joined
Nov 28, 2018
I just picked up an original Mississippi .54 (4th Model Harpers Ferry Conversion).. The bore measures out at .526. (micrometer and slugging barrel) I have a Lyman 54 Cal Minie mold that throws a .533 bullet. Is that to large to size down to a .525?? I really want to shoot it with a Minie if possible.
I notice that rifling is deep. I suspect a hefty charge is needed to expand that skirt to make it shoot accurately.

Thanks in advance for any input..
Cannonman
 

Cannonman1

Private
Joined
Nov 28, 2018
Here are some Pics ..
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FedericoFCavada

First Sergeant
Joined
Jan 27, 2015
Location
San Antonio, Texas
As you know, the original .54 used a .530 round ball with patching, hence the seven deep rifling grooves. Of course during the Civil War, most .54s were used with Minié/Burton bullets, so good on ya for trying to figure that out. As a general rule, for accuracy you'd want no more than a couple thousandths between the bullet size and the barrel size. On the other hand, if you want to simply use the authentic, mostly CSA .54 Minié/Burton bullet, top-accuracy-be-danged, that is another idea. I've seen CS Macon, GA arsenal Enfield cartridges developed using a paper-patched Pritchett type bullet, so if you want to "roll your own" Enfield-type paper cartridges rather than just use a measure and a box of lubed Minié/Burton balls, that is still another possibility.

As you definitely know, the Model 1841 was a favorite of Confederate mounted infantry/ flying columns, and popular with infantry as well. Mine is in .58, and while it currently lacks a front sight preventing use, I've modified mine like some of those altered by Colt... I just neeed to get the crazy yataghan bayonet for it I guess? Some of the better shooting I ever managed in a skirmish was with a borrowed, loaned .54 using Minié/Burton balls... Thanks very much for the pictures! These are such handsome long arms, no?
 

Cannonman1

Private
Joined
Nov 28, 2018
I have attempted to measure the bore and it seems a bit bigger than previously posted. The 7 lands makes that tricky !!. I think close to the .530. My Lyman mold throws a .533 minie and it won't start down the bore. I am having a minie sizing die made in .529 which is a moderate step down and should work well. They are beautiful weapons and probably my fav along with the 1855 Rifle. I will follow up with results and maybe some range data. Always love doing that kind of experimentation...
 
Joined
Aug 1, 2020
Location
Mid Hudson Valley, New York
That Model 1841 is one of the most beautiful US martial arms ever made with a lot of history going for it. And you have one that appears to be in exceptional condition as well as being produced in Harpers Ferry. Thanks for sharing the photos.

Bill
 

FedericoFCavada

First Sergeant
Joined
Jan 27, 2015
Location
San Antonio, Texas
The sights and the brazed-on side-mounted bayonet lug on your superb example would have been added much later... Possibly in the 1850s or 1860s. That one was certainly never "ridden hard and put away wet..." Superb condition.
 

Cannonman1

Private
Joined
Nov 28, 2018
Interesting that the adaptation of the 55 Rifle rear sight would not have also involved making all of this variation into .58 Standard caliber? Maybe it was early enough in the adoption of the .58 Minie/Burton bullet that they didn't want to throw all the eggs in one basket so to speak. Its survival in such good condition probably speaks to that. At that time the energy would have been in making 55 Rifles and Rifle Muskets. In Confederate hands it would have gone immediately into service but possibly not so much in the North which was focusing on .69 and .58.. Does that make any logical sense?
On Second thought.. We were importing lots of .54 Austrians so maybe its just the luck of the draw that some survived like that. I have certainly seen a few 55 Springfields and Mississippi's in pristine condition. They weren't all on the front line and collectors in past years who selected the better examples were both interested and probably capable of keeping them that way as opposed to someone buying one for hunting etc..
 
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Cannonman1

Private
Joined
Nov 28, 2018
I know the bore is less than .533 which is the diameter of the minie bullet I cast. It won't go down the bore but you can tell it is just oversized.. My guess is that bore is around .531. I have ordered pin gauges so we will soon see.
 

Don Dixon

Sergeant
Joined
Oct 24, 2008
Location
Fairfax, VA, USA
Bore comes out at .5325 which makes sense for seating a .530 round ball.. A .532 sized minie will work nicely.

I think you've hit on the reason your rifle is in such good condition. As I said earlier, the bore diameter measurements you were getting were curious. The ordnance standard bore diameter for a M1841 rifle was supposed to be .540 inches with an acceptable upward variation of .009 inches. Federal conical ball projectiles were supposed to be swaged at .5375 inches. Hence, standard Federal conical bullets would not have fit down the barrel of your rifle. Perhaps it then got set aside until it could be bored out to .58 caliber and re-rifled, which, like many of the Mississippis, never happened. [?]

Regards,
Don Dixon
 
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Noonanda

Private
Joined
Oct 19, 2016
Location
Fredericksburg Virginia
I think you've hit on the reason your rifle is in such good condition. As I said earlier, the bore diameter measurements you were getting were curious. The ordnance standard bore diameter for a M1841 rifle was supposed to be .540 inches with an acceptable upward variation of .009 inches. Federal conical ball projectiles were supposed to be swaged at .5375 inches. Hence, standard Federal conical bullets would not have fit down the barrel of your rifle. Perhaps it then got set aside until it could be bored out to .58 caliber and re-rifled, which, like many of the Mississippis, never happened. [?]

Regards,
Don Dixon
Don, but were not the tolerances all over the place? I mean the Burnsides were ".54 Cal" but the bore on most was .560+
 

Don Dixon

Sergeant
Joined
Oct 24, 2008
Location
Fairfax, VA, USA
Don, but were not the tolerances all over the place? I mean the Burnsides were ".54 Cal" but the bore on most was .560+

An economical vernier caliper capable of making accurate measurements to 0.001 of an inch [0.0254 mm] wasn't invented until 1851 when it was introduced by Joseph R. Brown [Brown and Sharpe] of Providence, RI. It was not until 1867 that Brown perfected the micrometer caliper. These are two of the most basic modern machinist’s measuring tools. So, you are correct that simply measuring things prior to and during the Civil War was a problem. But, you can't have weapons in which your bore is smaller than the bullets in your ammunition. The ordnance establishments in armies around the world issued their inspectors "go/no go" gauges to ensure that bores were neither smaller than their established ordnance standard nor larger. Anything that didn't meet standard was supposed to be rejected and condemned. Similarly, gauges for bullets and finished cartridges [where the bullet was loaded in the greased paper wrapper] were issued to the ammunition laboratories.

Re Burnside caliber, caliber designations are sometimes terms of art: the .38 Special, .357 magnum, 9mm, and .380 calibers all essentially measure .357 inches. What matters is true bore diameter and sizing the bullets to that.

Regards,
Don Dixon
 
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