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Loading Data for the .25 Roberts:
file:///C:/Users/Admin/Documents/Guns/Niedner-Sukalle%20Mauser/24HourCampfire-3.htm:
To make ammunition for a rifle chambered for the Niedner .25 Roberts, I would do as Ned Roberts did and start with 7x57mm brass. The 7x57 cases should be sized in your full-length .25 Roberts die, using a really good case lube like Redding's Imperial Case Sizing Wax. Depending on the resistance you encounter, proceed gently. You are going to have to move the case shoulder back, and increase the taper of the whole case body, as well as reduce the diameter of the neck.
The cases that emerge from the FL sizing process should fit the chamber of your rifle. If not, check the cases against your chamber casting.
The problem you may face is determining the overall case length. When you scrunch the 7x57 case to the .25 Roberts form, you will be moving a fair amount of brass, and it is likely to make your cases longer than they should be. In the 1935 article, Roberts wrote that one of the reasons Griffin & Howe proposed their version of the .25 Roberts was that it decreased the amount of neck trimming required on the formed cases. Since you evidently have the shorter-necked Niedner version, you will probably have to trim the formed cases to avoid the problems of a too-long neck. You might contact the maker of your dies to find out what are his recommendations. Hopefully he will have the length dimension of the .25 Roberts Niedner version, and not the .25 Roberts G&H version. (Roberts wrote that the G&H case is about 1/16-inch longer than the Niedner case.) If he does not have a max cartridge length measurement in his files, you might contact one of the knowledgeable IAA persons.
It's possible and even likely that the cases produced by FL sizing of 7x57 cases may not require fire-forming of any kind. After trimming, the cases may be ready to load, just like factory brass. However, until you're sure of this, some initial trials using the cream-of-wheat forming technique may be advisable. If you happen to make and fire a case with a too-long neck, the c-o-w method doesn't produce the possibly dangerous pressures that may occur with a bullet in place.
There's also the question of whether the headspace of cases formed by the FL die is correct. (I recently worked through a problem of a FL die headspace mismatch to the chamber, which produced case head separations.) Some c-o-w firings may reveal any difficulties here.
Good luck.
--Bob
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On 12/8/2014 11:23 AM, The 310 Shop wrote:
David,
Yes Ideal did make dies for the 25 Roberts. Had a catalog die number of #159. I will look to see if I have a neck sizing die (MR die) or a bullet seating die (DA die) so marked. Give me a day to dig around. From what I could find on the internet, reference books on hand, the 25 Roberts was a shortened and necked down 7x57 case (2.160”). Some time later….early 1930’s the major manufactures (Remington and Winchester) decided to just neck down 7x57 brass and call it a day. Mr. Roberts agreed with the idea and the rest is history. Remington first called it the 25 Remington and then Winchester called it the 25 Winchester then they both added the Roberts name…..THEN, it was changed to the 257 Roberts so people won’t try to chamber 25 Roberts rounds in the longer chambers. Confusion confusion. dAgain, let me take some measurements of 257 Roberts dies to see if they will work for the 25 Roberts. The only unkown for me right now is if the bullet seating die is to long for the 25 Roberts lip to reach the crimp step. I think it might be the case. If so I can shorten the die about .600” to fit your needs. That would be no problem to do in the shop.
For making brass you will probably need a (some) case forming die os dies. C-H Tool & 4-D Custom Die Co is the ones to go to for those. 740-397-7214 or 740-397-6600. I would think just one form/trim die would do it. Just run the 7x57 shell into the die until the shell holder hits bottom, trim the part sticking out the top with a hack saw then file flat with a flat file and neaten up with a chamfering tool and load. The shoulder will look odd until you fire form the brass after which all is good. Welcome to the world of shooting odd stuff. It’s fun, it’s expensive, it keeps you out of the bars!
Oh one other thing. With the 310 dies you only neck size brass. They were designed that way. So as long as the neck diameters are the same and the shell body will fit into the die then a 310 die for a .257 bullet will fit. Actually a practice that Ideal and then Lyman used all the time. Since the 257 Roberts uses the same shell body as the Roberts then again the only difference is the length of the seating die. That’s why the 25 Roberts had a catalog number of 159 and the 257 Roberts had a catalog number of 166.
Any questions call or email.
Take care and have fun with all this,
Rick
The 310 Shop
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David,
What I was referring to there was using conversion dies to convert 7x57 shells to 25 Robts dies. The conversion die allows you to run the 7x57 all the way in trim off the excess sticking out the top, clean up the rim then load the shell and shoot. The shell would form (fire form) to the chamber and look correct. Sounds like you purcheased reloading die for the 25 Roberts. You might want to call Dave Davison back and see what would be the best way to convert the 7x57 shell to 25 Roberts. Maybe trim to length first then size them in the sizing die. Call first to make sure. Some cases you can do that with others maybe that extra forming die is needed.
Let me know what he has to say.
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