Forming 6x58 Forster rimless brass

[Shovelhead]

I need to form some 6x58 Forster brass for an old German rifle. I think that the best brass to use is 25-06, is it simply a one shot reform with the 6x58 full length die or do I need an intermediate die? Thanks, Shovelhead.

[EDG]

I have formed cases with a lot more reduction so it should be an easy forming job.
I have been an avid reloader and case former for more than 50 years. I have never seen 6x58 dies offered for sale.

[kr54]

Why not start with 6mm Remington or 257 Roberts? I think with the 6mm, you could expand the neck to 257 and then neck back down to 244. This will form a new small shoulder. Place the new shoulder to the correct headspace and fire form. I would think that the forming or a few shots would bring you up to the trim to length. Then just neck size in the 6mm dies.

[Shovelhead]

I have been reloading about 12 years but this is the first brass I have had to form. The 6mm brass is too short, I don't know about the 257, I was told that the 25-06 was the case to use. The diameter of the extractor groove for the 6x58 is smaller than the SAAMI standard for the 25-06, I found that Hornady brass was well below the SAAMI standard and right where I needed it for the extractor to function. The extractor is a complicated claw type that wraps around the base of the shell. My reforming process was anneal brass, form, trim to length, anneal and run thru form again. I used Hornady Unique case lube. I made 10 cases to try but it took me 18 cases, the 8 cases got wrinkles in the shoulder area and I wouldn't use them. I didn't know if this rate of failure was normal. The final cases look great and I will try them soon. I was very lucky to find a set of RCBS 6x58 Forster dies at an estate auction of a European collector. I would appreciate any feedback.

[EDG]

You need to use less lube. Use about the amount you have on a greasy, sweaty nose.
Do not try to form the 25-06 in one stroke. Form about 1/4" at a time. If you find a ring of lube on the case wipe it off and form another 1/4" keep forming until you get each case finished.

You can use once fired brass and it probably doe not need annealing until you have formed it and fired it once.
At any rate you do not have to develop your process with new brass. Just find some .270 once fired brass for process development. Once you get your process developed form the brass you want to use for shooting.


I have been reloading about 12 years but this is the first brass I have had to form. The 6mm brass is too short, I don't know about the 257, I was told that the 25-06 was the case to use. The diameter of the extractor groove for the 6x58 is smaller than the SAAMI standard for the 25-06, I found that Hornady brass was well below the SAAMI standard and right where I needed it for the extractor to function. The extractor is a complicated claw type that wraps around the base of the shell. My reforming process was anneal brass, form, trim to length, anneal and run thru form again. I used Hornady Unique case lube. I made 10 cases to try but it took me 18 cases, the 8 cases got wrinkles in the shoulder area and I wouldn't use them. I didn't know if this rate of failure was normal. The final cases look great and I will try them soon. I was very lucky to find a set of RCBS 6x58 Forster dies at an estate auction of a European collector. I would appreciate any feedback.

[Shovelhead]

I will try what you say about less lube, partial stroke and cleaning excess lube. The 25-06 I am using is once fired. The 270 brass, at least the Rem I have, will not work. The SAAMI standard dimension for the extractor grove diameter .409, the Rem 270 I have measures .406, anything larger than .395 will jam the extractor and you cannot close the bolt.

[Mk42gunner]

I don't have any reference books handy that show your 6x58 Forster cartridge dimensions, so just about everything I write will be a guess.

1. If the diameter of the extractor groove is the main hangup in converting brass, you will always have to check parent cases.

2. I too think the .257 Roberts or 6mm Remington would make suitable, albeit short by 1 mm cases. This may or may not matter.

3. Even though you .270 brass won't work because of the extractor groove size, you can still use it to improve your case forming technique.

4. I would do the all the case forming I could before annealing. I have found it better to form harder brass, it seems annealing weakens it enough to welcome failure. Basically for me annealing is the absolute last step in the process.

5. If you have any shorter reloading dies such as the almost anything from the .308 family, except .243, you can push the shoulder back with them first.

6. This seems to me like a quite rare rifle that you just want to load a few rounds for, not something you are planning to take prairie dog hunting an run thousands of rounds through, right? If so you can accept a few more failures while forming cases to get 50-100 cases, which might be a lifetime supply.

Good Luck

Robert

Almost forgot--

7. You may be able to turn the extractor groove deeper in a lathe or drill with a file, maybe not the best option, but it may work.

R

[Shovelhead]

I have the specs for all the cartridges you mention as well as the 6x58, German, first produced as an experimental round in the 1890's, accepted as a standard cartridge in 1902 and produced until the mid 1930's. The problem is the extractor groove dimension, the extractor is a claw type that engages the rim for approximately 90 degrees around the groove, so if the groove diameter is oversized, over .396, the extractor will not sit flush with the bolt body and the bolt will not close. Yes, the rifle is rare and I will be happy with 20 good cases. The Hornady cases I have for some reason have the extractor groove cut much smaller than the standard, .392-.394, so they will work, I just have to practice my method. Thank you for the suggestions, I will try them out.

[Wayne Smith]

If you have once fired or new brass try your initial sizing with less lube and multiple small steps as described prior to annealing. You haven't mentioned shoulder dimensions, if you are forming it or fire forming it. When I make 25 Krag AI I neck size the brass, anneal, and fire form the AI and shoulder expansion. The 30-40 Krag has a one caliber neck length as does the 25 Krag AI so I am expanding the shoulder up into what was the neck. When I fire form without annealing I get shoulder splits 100% of the time. Annealing drops this to around 2%, probably because of uneven annealing.