.58 Mont Storm


Hi all

Could someone help me with more information about this RF cartridge? Manufacturer? Year?

Case length: 31mm
Case diam.: 16,5mm
Rim diam.: 18,8mm
Total length: 48,5mm

subefotos.com/ver/?749f013bef355 … 13e1fo.jpg

The unit on the left is a 44-40 WCF.



Hi Daniel,

If you have John Barber’s book, The Rimfire Cartridge in the United States and Canada, pages 150, 151 give a nice overview of it with pictures of some super-early boxes, cartridges and xrays.

Yours is the UMC variation which was loaded in South America. UMC actually designated it as the .58 Roberts Converted Enfield, or .58 Roberts Converted Springfield. Both the 1869, and 1871 price lists list it: cartridgecollectors.org/content/ … %20UMC.pdf

William Mont Storm originally patented the conversions from the percussion muskets to the metallic cartridge in 1856 and 1859, google.com/patents/US24414

The US government purchased the rights to modify 2000 muskets. Leet, Goff & Co made some cartridges which were tested in The 1860 Ordnance Trials. Then in 1866 Roberts patented (google.com/patents/US52887) a musket conversion. UMC then made the cartridge with the exact same specs as the Storm, but named it the .58 Roberts as mentioned earlier. Crittenden & Tibbals made a .58 Roberts, UMC made 2 variations and then there is a .58 Roberts with a raised H, thought to be by WRA.

So technically you have a .58 Roberts, but Barber suggests calling the cartridge the .58 Storm/Roberts


Daniel, this cartridge was loaded in Brazil. I posted some information in an earlier post about the so-called “Krnka” cartridge:

"This country [Brazil] is known to have bought 5000 .58 caliber Roberts rifles in 1867. Rimfire cartridges for these rifles were bought as NPE cases and then loaded locally, but their quality was terrible and these gave very bad results during 1868, the first year of the Triple Alliance War against Paraguay. These cartridges are the so-called “.58 Mont Storm, South American load” and have profound and irregular bullet crimps.

During the third term of president Luís Alves de Lima e Silva (1875-78) it was ordered that all rifles in service had to be modified to center fire, including Spencer and Winchester Model 1866 rifles. Several types of center fire cartridges were made locally and in Europe for these last two weapons, but a center fire version of the .58 Roberts cartridge is not known to have been made locally or imported to Brazil. Also, during 1870-71, after the war was over, at least 1000 of those Roberts rifles and thousands of cartridges were sold to Argentina".

Aaron, this cartridge is not listed in any of those UMC price lists and the .58 cartridges mentioned are center fire and not for Roberts conversions. I believe that the only UMC reference showing a .58 Roberts rimfire is a cartridge board made c. 1875 where is listed as “.58 Robert’s Altered Enfield Rifle”.



That info about them being in those price lists is from Barber’s book. Maybe he was confused.

If I squint, and look closer at those, I guess it does have a ditto mark under “central fire.”

I think here is an image of that 1875 board too. It is too small and of low quality, so I can’t make out the words of what it says.


Aaron, that is a later c. 1877-78 cartridge board and doesn’t include the .58 Roberts rimfire, only the “.58 Musket” and “.58 Gatlin”(sic). These two are shown at right on the fourth line.

The one made c. 1875 is similar but it doesn’t include B. B. caps, pinfires and the “What Cheer” line, for example.


Do you have any pictures of other boards like this? I have been told that there is no way to accurately date them for sure as they seemingly randomly had a few different cartridges on them.


Yes, that’s true, the method used to date these boards is solely based on the newest cartridge found. However, every cartridge on these boards is labeled, not just randomly added.

As to their approximate date, the so-called c. 1875 board shows the .44-60 and .44-77 Sharps and the so-called c. 1877-78 board shows the .40-70, .40-90 and .44-100 “What Cheer”. None of these cartridge were made before that date.

This is a c. 1875 board (the .58 Roberts is the first one at right on fourth line):


I am not trying to be difficult, but is it technically an assumption that those cartridges were not around until 1877, when we do not have any pricelists/catalogs from 1874 and 1876? (Or do we have patents for them that date them to that range?)

The reason I even care, is because I have a piece of one of these boards. (The pinfire section, naturally,) and would love to date it with a little more certainty. Why would they not have them on the earliest boards when pinfires had been made by them since their very first catalog. (Also, while on the topic, why, before 1880, do only 1866, 1873, have pinfires listed, while the others do not?)


Aaron, the What Cheer Range in Greenwood Rhode Island was opened on October 25, 1875 and the .40-70 and .44-95 to 115 “What Cheer” cartridges and the rifles for them were not mentioned by Providence Tool Co. until advertisements published in 1877 and then included in their August 1st, 1878 catalog. The .40-90 was listed in Winchester’s May 1, 1878 catalog. Also, none of these is included in E. Remington & Sons’ 1877 price list.

These are the reasons why in mi opinion the board you are showing can’t be earlier than 1877 but I’m afraid that I can’t explain why an earlier board doesn’t show pinfires and a later board does. Also, there are many rare cartridges found in boards only which means that is hard to understand what was going on inside the board maker’s head.


I agree with Fede on Boards. They are hard to figure out sometimes. Years ago I purchased a small S.F.M. Board that I thought, from the cartridges on it including all .22s on the board having copper cases, that is was old - perhaps from the 1920s or earlier. About a year later, I got a second board, which turned out to be identical to the first except for two things - it was sequentially the next printing number, and one of the older calibers was replaced with a .222 Remington (yes, with the name printed identically to the other cartridges on the board itself, so not a replacement). Obviously, both my boards are post-WWII.


Come back to this topic, I have adquire a new .58 Mont Storm/Robert South American load.
Comparing the two units, one has 6 crimp marks while the other has 7 crimp marks. The size of the marks as well as the depth are different between the two units, this is a picture of both units:

subefotos.com/ver/?d6c5be70442f1 … 9b3d2o.jpg

As these cases were loaded locally and their quality was terrible and these gave very bad results during the first year of the Triple Alliance War against Paraguay as Fede mentioned. I am wondering if these differences in the number of crimp and size was a tool change as an intention to improve the quality of the cartridge.
Someone could bring some information on this?