Winchester 1885 Low Wall problem…

Here is an interesting problem to solve.  I have a Winchester 1885 Low Wall with a single set trigger and peep sight on the upper tang.  The serial range puts it at 1887.  It is an early Low Wall as it has the high block and not the scalloped block on later models,  It has the scalloped receiver and not the flat surface receiver as on later models.  The action shows some patina, but is very sound and tight.  It came to me without the butt stock (Butt stock on order from CPA). The barrel is a #1 and was stamped on the top flat of the barrel .22 LONG.  The barrel has been rebored and rifled by J. Stevens A&T Co. some time along the line, but the new caliber stamp was not applied.  It is in .25 caliber, appearing at first to be 25-20 Single Shot with the extractor fitted and the firing pin made to CF. I got hold of some new manufactured smokeless loaded cases from Buffalo Arms in 25-20 SS, RCBS die set, and some cast bullets. The rifle was cleaned and inspected and found to be sound.  I inserted the 25-20 SS round into the chamber and it does not fit, as it will fall under the extractor and is a loose fit in the chamber.  The extractor is cut too large to catch the 25-20 SS rim.  

So now I am thinking, what is going on here!  I cast the chamber and took some measurements.  The OAL and profile is good for the 25-20 SS (and not 25-20 WCF or .256 Win Mag) as no sharper shoulder is present. Taking measurements of the rim area at the breach end and extractor, it fits the 38/357 rim diameter perfectly.  The chamber is larger in diameter at the head too.  So now what is really going on here?  Has it been chambered for some obscure cartridge that used the 38/357 case head, 25-20 SS shallow taper profile, OAL and in .25 caliber?

I have a few choices and I will list them here.

1-Cut the breach end off, rethread, fit and chamber to 25-20 Single Shot, fit a new extractor.  I have the die set, and cases. I would have to rent the 25-20 SS finish reamer. Re-fit the forearm and main spring attachment point.

2-Install a barrel liner in 25-20 WCF from Brownells, fit the new extractor.  I would need to buy the deep hole drill and liner from Brownell. 25-20 WCF die set, cases and rent the finish reamer..

3-Set the barrel back, rethread, fit and chamber to .256 Win Mag.  I would not need to fit the extractor as it would fit the case head just right.  I would need to purchase a die set, cases and rent the finish reamer. 

I’m leaning on #1

As stated above the chamber cast has been performed.

I shoot a 256 Mag in a Martini and Ruger #1 at low pressure though the actions can tske hotter loads.
the advantage is it can be made from cheap available 357 brass.Loaded to low pressure levels it's a nice cartridge to work with.
Cases easily formed with a standard Redding or RCBS set using the seating die as the initial form die running it in about 80%.

just my take anyhow

25-20 SS wrote on Dec 8^th, 2023 at 4:08pm:

Can you give us the dimensions of the chamber cast.

Like taper, per .100 in length, neck diameter and length. Any shoulder, if so, dia and lg.

Unless you can reproduce the cartridge case, a reline to .25 caliber and a rechambering is likely the simplest option.  Shortening the barrel means the loss of the base position for the mainspring, a gap in the repositioned forend as the barrel tapers, and a new extractor cut will also be needed.  Not to mention the loss of investment you’ve already made in ammunition, bullets and dies.

Short of that, the chamber might be bushed with a soldered-in piece of old barrel, and the bushing rechambered.  This if the unknown chamber is short enough for a reasonable throat length.

A picture of the chamber cast would definitely help here.

each square is 1/4"
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357 head/rim in chamber
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25-20 SS in chamber
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diff in head size
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it looks like your rim seat is a little generous, but the rest of the dimensions look OK, for moderate loads at least.

I also had a .22 Long Low Wall that I had Redman rebore and rechamber to .32-20 back when he was doing such work.  I had him do the rimfire extractor the way yours is for the larger centerfire case and sometimes I wish I had all my extractors like that.  Very positive and no possibility of sneaking a small rim past the hook.

Is there some reason that you don't want to use the chamber that it has?

357 Max brass can be formed to your chamber. I can walk you through how to do it.