Sharps 40-70 Fire-formed case mystery

Gentlemen,

Hoping I could get some advice from the expert sportsmen of black powder arms here.

I have an original Sharps “Old Reliable” caliber 40-70. I was told by the dealer who sold it to me, it was bottleneck cartridge.

I purchased a box of 40-70 BN from Buffalo Arms. I fired a few shots at close range and immediately noticed key-holes in the target paper. I was only about 10-15 yards.

I saw that the fire formed cartridge did not match the profile of the BN design, so I figured I must have the wrong cartridge for my chamber.

However, the straight wall-cartridge (also from Buffalo Arms) is too narrow. My fire-formed case has a consistent “.50 diameter (same as the BN cartridge base) all the way up the case wall.

The straight cartridge will chamber, and the block will close on it (it’s quite a bit longer than the BN cartridge).

I’m assuming neither cartridge is correct for my rifle and that the fire-formed case should match the profile of the unfired BN case. The bore does gauge at 40 caliber.

Does anyone know what this chamber could possibly be? Are there others like this?

Thank you,

I’ve linked some photos of the fire-formed cases next to the loaded cartridges from Buffalo Arms, and some pictures of the rifle markings.

https://drive.google.com/file/d/1iYs...w?usp=drivesdk

https://drive.google.com/file/d/1u2a...w?usp=drivesdk

https://drive.google.com/file/d/1-8p...w?usp=drivesdk

https://drive.google.com/file/d/1ASZ...w?usp=drivesdk

https://drive.google.com/file/d/1Fna...w?usp=drivesdk

I'm unable to view your photos goole says access denied but your best bet would be to do a chamber cast and find out exactly what you have its quite possible someone changed the chamber dimentions during the rifles history.

Get some creosafe, i think its called, for chamber casting, brownells sells it, low temp to melt, gives time to get it out, then it swells to get demintions from> then you can see what cartrage you might have ????

The chambering should be stamped on the barrel
If it’s 40-70 it would be 40 with possibly a 2 1/2
Common groove diameter of the 40’s of the day was .403
Sharps did chamber a very few rifles in 40 2.1
Which is quite similar to what we call a 40-65 now
But there’s no telling what abuse that rifle may have been subjected to by someone with a brand new harbor freight crescent wrench and a memebership to reamerrdntsls are us

Thank you all for responses so far.

I made the photo links public access, so they should be available to see now.

The barrel is stamped 40 caliber, 70 midrange.

The bore gauges just a hair over .40 which is what Don was mentioning.

Don, is there any information on the 40 2.1 cartridge data available? Making a custom case would be a pain, but at least I could determine if the chambering is original or if it was messed with over the years.

Just from looking at the case next to the .40-70 BN it looks like that might be the .40-90 necked Sharps chamber. That chamber was a fore runner to the .40-70 Sharps straight and it was used for the matches with very good accuracy from the records I have found for this chamber. I once considered having a reamer made for this caliber. I don't remember the case length but 2.650" seems to stick in my mind. You might do a little research for this caliber.
Also to get a good enough chamber cast to see what your chamber looks like make a cast using candle wax or canning wax you can get from Walmart. Clean the chamber and bore good and leave a very thing coat of oil in it and push a couple patches in from the muzzle end stoping about 3" from the breach and make your cast let it cool and push it out from the muzzle.
I do this simple cast when I want to get a look at what I have for a chamber. The wax cast is good enough for what your wanting to know and the wax will not do any damage.
Blow is a cast I made for the .44-75 Ballard chamber.
Attachment 304072

40-65, 40-70 Bottle Neck, 40-90 Bottle Neck all use 45-70 base
40-70 Sharps St, 40-90 Sharps St both use a smaller size base.

Quote:

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Originally Posted by beshears

40-65, 40-70 Bottle Neck, 40-90 Bottle Neck all use 45-70 base
40-70 Sharps St, 40-90 Sharps St both use a smaller size base.

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Would it be possible to have a chamber for 40-90, while the barrel is marked “70 midrange”? Or are we dealing with a post manufacture re-chambering without a doubt?

Looks like from the pictures it should probably be a 40-90 bn now but I don’t think it started that way

Looks like it's been rechambered to something longer than 40-70BN. No telling what could have happened in the last 140+ years. By the profile of your case, you still have a longer neck to find in there somewhere. The chamber cast is the way to go.

A lot of the original .40-70 BN were marked midrange and some place on the barrel was a #3 stamped for a #3 midrange. I have seen one rifle with a 3 just in front of the forearm

Almost certainly re-chambered to .40-90 SBN by someone after it left the factory , as was previously suggested. Get some Cerrosafe (or some elemental [pure] sulfur, which also works very well, just more fragile) and do a chamber cast. .40-70 SBN and .40-90 SBN : Same rim, same head, same body, just overall length and longer body to the shoulder.

I'm with Don......somebody went wild with a reamer.