Neck stretching on a 30-40 Krag case

[MOA]

I need some experienced ideas on using (if possible) current reloading dies in a step by step process to open up the krag case to a .410 size. My intent, it to load Lyman's Rifle Bullet Mould: 405 - #412263 2640263. I have a SB2 in 30-30 that I want JES to rebore to .410 and chamber for the stretched krag brass. This cartridge is close to the 40-70 SS except is is a bit shorter which is fine with me, the .25 inch shortness is not a problem at the shooting distance I plan on using it at. I haven't yet contacted JES about this work, or if they are even able to do it. The main issue on getting it done is there may not be a reamer currently made to use the standard length that the krag case is left at after opening up the mouth to that diameter. Shiloh uses this case for their 40-70 SS chamberings, but, they have buffalo arms not only open the case mouth but also stretch the case to the accepted 40-70 SS length. I want to use the case without stretching the length, just opening the mouth. Anyways, I have many reloading dies covering many calibers. If I can slowly open this krag case I can then use my 40-70 SS, or my 450/400 N.E. dies to load a dummy case with this boolit and if needed send it to get a reamer made, I just need to get the mouth opened up in an acceptable manner to get this dummy made in case I need one since I have no way to fire form the case at present. Thanks in advance for all the suggestions.

[15meter]

Try Redding, they make tapered expanding buttons just for neck expanding, I used one to convert .243 Winchester to 260 Remington and it worked quite well.

Imperial sizing lube applied to the inside of the case mouth with a q-tip is your friend.

[Bent Ramrod]

I believe there is a wildcat called the .40 Krag, which is the normal length Krag shell blown out straight. You could still use your .40-70 dies for sizing and seating; might need a taper crimp die if you want the boolit held tightly. JES might have a reamer, or perhaps you could rent one.

My general rule for case reforming is: Dies for shoulder setback and neck reduction; annealing and fireforming for neck expansion and body increase. Just finished my first box of Cream of Wheat after 30 years of blowing out shells and had to buy another one. Why is the stuff so expensive? I wouldn’t eat the glop unless I was starving, but it is thee prescription for case forming.

[ipopum]

I use plain old corn meal. It will be cheaper.

[MOA]

I believe there is a wildcat called the .40 Krag, which is the normal length Krag shell blown out straight. You could still use your .40-70 dies for sizing and seating; might need a taper crimp die if you want the boolit held tightly. JES might have a reamer, or perhaps you could rent one.

My general rule for case reforming is: Dies for shoulder setback and neck reduction; annealing and fireforming for neck expansion and body increase. Just finished my first box of Cream of Wheat after 30 years of blowing out shells and had to buy another one. Why is the stuff so expensive? I wouldn’t eat the glop unless I was starving, but it is thee prescription for case forming.

That's the issue I have Ramrod. I have no chamber to fireform the krag brass in. I need, as I lead with in my question a way to form the case using sizing dies a bit at a time. From my memory my dies on hand that might apply....06, 7.62x39, 9.3x74R, 375 Win, 450/400 NE., 40-70 SS and lots of inside neck lube. This brass was annealed once already.

[EDG]

The cartridge you are wanting to make is the .40-70 Maynard. Check Cartridges of the World.
Check the ASSRA forum for guys that shoot it and know how to form it.
It is an old single shot round.
Champion shooter named Steve Garbe used to compete with one.
He knows how to blow out the brass.

[Gewehr-Guy]

Maybe fireform them in a .410 shotgun and see what you come up with for dimensions.

[MOA]

Maybe fireform them in a .410 shotgun and see what you come up with for dimensions.

Great idea. I just fireformed some 410 shells out of 9.3x74R earlier this year. Rim dimensions are within where it should chamber. I'll give it a try. I just sent off a letter to JES Reboring this morning. It would be sweet if I only have to send the barrel, but they will most likely want the complete firearm to test it......maybe. From what I've been able to find over at the single shot rifle forum the 30-40 krag blown out to 40 cal was referred to as a 40-60 Maynard. I'm looking forward to this project.

[Gewehr-Guy]

If you blow them out in a .410 chamber, then run them back up a 30-40 die till the mouth of the case touches the shoulder in the die, it should come out about .425 OD. Then a M expander die or NOE plug in a Lee die.

I wonder if such a cartridge would feed through a rebored Krag?

[Mk42gunner]

My first thought was to expand the necks to .35 cal using a tapered neck expander like in the RCBS .35 Whelen set. Then I read your list of dies and realized that is quite an expense for a one time use die.

Robert

[15meter]

If it has been annealed recently and not been work hardened again through multiple firings, be careful when you try expanding the neck, move it slowly in small increments. If the brass is too soft you have a chance of crumpling the neck. MOST of the time it is better to try and form when the brass is reasonably hard.

It is a bit of a balancing act, trying to find the happy median between too soft and crumpling shoulders and too hard and splitting the necks.

If you have a .410 available, that may be an option for fire forming, just recently as a "house arrest" project I fireformed some 444 Marlin cases in a 410/45 Colt chamber in an effort to create a "45 Ridiculous Colt" -- an extremely long cased 45 Colt to use in a T/C with a 410/45 Colt barrel where there is a veeeery long jump to the rifling when using standard 45 Colt brass.

Worked pretty good, my fire forming loads were a little on the light side, could have used a little more powder to blow them out completely.

[15meter]

This is what I posted earlier about:

https://www.redding-reloading.com/on...d-size-buttons

There appears to be a hitch in their webpage, used to show various sizes available, "expands from caliber x to caliber xx" kind of chart. My Google-Fu is weak tonight, I can't find it but at least you can see what the taper expander looks like.

[MOA]

My first thought was to expand the necks to .35 cal using a tapered neck expander like in the RCBS .35 Whelen set. Then I read your list of dies and realized that is quite an expense for a one time use die.

Robert

Robert, I think you are correct in reference to opening up with some expander buttons. As to the expense of the dies, those are dies I already own for reloading those calibers. I have close to thirty die sets in different calibers since I load for that many different calibers. I was just pondering if it was possible to use them in stages just enough to open up the shoulder and mouth of the krag case without purchasing extra dies and equipt. I have ordered from NOE yesterday four expander buttons that will fit my Lee universal decapper as so many here on this site have mentioned. I hope they will get my 32, 35, 38, and 41 buttons on the way soon.

[Mk42gunner]

I was referring to buying just the .35 Whelen die for a one time use, but it sounds like you are on the right track with multiple expanders.

I will second 15meter's warning about trying to neck expand annealed cases, every time I tried it it resulted in a collapsed shoulder. Maybe I was annealing to much?

I do know I fall into Grumpa's camp of doing all the forming I can before annealing.

Anyway, good luck with it, your proposed rifle sounds like a lot of fun. Plus I get a kick out of having uncommon rounds.

Robert

[MOA]

Mk, yes, I think I will try to fireform in the 410 first to open it as much as possible to avoid splitting. Having the extra buttons will be a plus if I need them and if not no big deal. Sometimes life is just one big Catch 22.

[Yooper003]

I know it is a little off the the origin of this thread but, I could not believe how easy it was to open 06 cases .050 . I had never done this before. A little bag balm on a q-tip & 1 pass with my lee 35 whelen die & 35 whelen cases. The only other forming I had done was reducing, making 7-08 from 308. Both have worked great, maybe I have just been lucky.

[Texas by God]

Sadly, the 30-40 rim is too thick to chamber in a .410 single shot. I just tried it with unprimed brass; close but no cigar. Dang it for you.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[MOA]

Sadly, the 30-40 rim is too thick to chamber in a .410 single shot. I just tried it with unprimed brass; close but no cigar. Dang it for you.

Sent from my SAMSUNG-SM-G930A using Tapatalk

Thanks TbG. I hadn't got the chance to push one into the Mossberg yet since we're in the process of packing to head back to Az. But I did get the assortment of expanders from Al over at NOE a week or so ago. So, I'm at least ready to go that way when I get setup again. Now, I do have some extra 9.3 that could be shortened or just opened up to forty cal too.

[Hiwall55]

I have 2 40/60 Maynard and can fireform a case for you. My chamber is 2.2 and I cut Krag brass down a little before forming them, but could form a standard case and send it to you. I always used a 40/70 reamer but only run it in short.

[MOA]

Thanks Hiwall. I'm researching if any or much difference between the 40/60 Maynard and what is called the 40 Krag. The work will be done by JES so if no real difference I'll just fire form the cases in the new cut chamber. I thank you for the offer. Will keep this thread updated as this moves along.