Krag bolt interchangeability

[FredC]

I gotta apologize, all the hoops we made you jump through to address this issue. These Grafs cases have been around for several years. I bought some way back when just after they became available and measured the rim thickness and cut the head end in half on one to look at the web thickness of the head. All looked good and we had reports of people using it with no issues, so all is right and good in the world. Photo shows 2 cases with the same issue as your first photo from this morning.
I was just so sure that the brass was not the problem and did not do a simple test.
Seems like Parashooter's idea of setting the shoulder back a little with the 308 die might be a viable solution. Another idea would be to take a dedicated resizing die and cut some off the bottom face till it works with your Krags. Seems like sooner or later it would become an issue with Remington or Winchester brass. I have a surface grinder here and could do it so the job would look professional.

Did some more checking and the Grafs cases are not sitting as proud as I thought yesterday more like .010 or .015 about 1/2 of the bolt closing cam.
Anyway I am thinking there was a change in the distance of the bolt to the shoulder from the armory. Remington and Winchester knew about it and made brass accordingly and Grafs missed the memo.
Below are the serial numbers and comments of for 2 Krags. Maybe Br can find the drawing with the change and date on the length of Krag chambers and we can get better answers.

Receiver and barrel #266389 does not play well with Grafs' brass
Krag rifle#397810 a little resistance closing the bolt on Grafs case telltale ring on the shoulder was present
Pulled barrel from #410854 40+ cases drops in and each rim touches the barrel

[butlersrangers]

I'm definitely mentally wandering outside my 'pay-grade':

WAG - Maybe the maker of Graf brass used a different process in annealing case necks and shoulder area during manufacture, adapted some equipment from .303 cartridge-case making equipment, or just used different measuring standards?

I agree with FredC. Remington and Winchester have been making .30-40 ammo for a long time and likely learned to accommodate all .30-40 chambers. If Graf brass is a bit long in the shoulder for Springfield .30-40 chambers, the shoulder can be moved 'back'.

Many cartridges from the 1885 to 1920 era do not exactly match SAAMI standards devised at a much later date.
It is not unusual to encounter case and Die problems when loading for old military rifles.
There has been a lot of development and evolution going on.

It was not long ago that a KCA member was experiencing feed-jams (with Hornady .30-40 ammo, I think). The problem appeared to be that the maker was not putting the "bevel" on the edge of the cartridge rim. The Krag rims were beveled for a purpose!

(p.s. If the case bevel is largely absent, it can change how the case engages the bolt face.
A Krag's 'flanged' bolt-face is not necessarily perfectly "square".
If the bolt-face is slightly 'dished' or concave, a case with little 'bevel' will make contact at the edge of the rim. A case with a pronounced bevel will bear more centrally on the bolt face.
This difference, may in effect, change free-travel several thousands of an inch. In some Krags it may possibly allow the case shoulder to make chamber contact)?

[Parashooter]

For a handloader, the simplest solution to this kind of minor shoulder interference is just to use a bit more muscle to close the bolt when chambering the "tight" cartridge. On firing, the case will acquire the dimensions of the chamber (AKA "fire-form") and, thanks to the natural elasticity of good cartridge brass, is likely to chamber readily if neck-sized and loaded again.

Should this be ineffective, I would take some height off a cheap shell-holder rather than alter a sizing die. Easy enough with nothing more than some 180-grit wet-or-dry paper and a flat surface.

[FredC]

In order address:
Br my bolt that I used was a stripped NOS, bolt face is very flat. Not the problem, sometime ago we discussed a drawing of a change in the rim to shoulder in a drawing. I can not remember the date and serial numbers involved in the change. Drawings with the change were presented by you. Looks like it is a real thing we just banged our heads into now. I thought it was non existent till now.

Parashooter I thought about just shooting them also. Maybe in straightening out the big radius in the corner would cause the angle to pull back and the issue would go away in later use of the brass. No clue without experimenting. If the extra effort to close the bolt did not go away after the first firing it is kind of abusive to the bolt and receiver lugs. A little extra lube there would help if it was one time and done thing.

Modifying the shell holder is an elegant solution. Sanding to take a couple of tenths off is not too hard, taking .005 off may take quite a while and be harder to keep the surface parallel without a mike. If Zac wants to send me a shell holder I can face it off in a lathe or surface grind it in a minute. Either way no charge as I feel responsible for starting him off on this wild goose chase.

[Parashooter]

Since the upper surface area of the shellholder is relatively small, sanding away 5 or 10 thou' by hand actually goes pretty quick. Doesn't really matter if it's parallel since we adjust the die only far enough to size case to fit chamber, rather than to touch the trimmed-down shellholder. Sloppy but practical.

[Zac952]

Fred thank you for confirming this on your end, and your not responsible for this wild goose chase, I too didn't believe that both the Graf cases and resizing die would have been the problem, I plan to get a case comparator that measures base to shoulder and I will likely just stone my shell holder down until the cases match the remington brass (provided it chambers freely which so far it seems as it will) I do appreciate the offer from you to machine it down though! All in all it has been a great learning experience, and I now know the Krag rifles much better than I would have if everything had gone right in the first place, and it has hopefully helped out the community by documenting it in the process. In Joe Poyer's book on the krag rifle he mentions a change in the chamber dimension sometime during the 1898 model, ill have to find the page once I'm off work. I will likely separate my Graf brass and keep it handy if I have a headspace problem in the future as if it has a longer base to shoulder it should help with some worn out Krag rifles or carbines as it will likely headspace off the shoulder ensuring the base is tight against the boltface in firing. All this tinkering has just emboldened my passion for Krag rifles and hopefully one day I will find an affordable Carbine or possibly a true school rifle to add to my collection, or maybe I'll have to get my wife to redefine "affordable" lol. Anyway thank you to all who have helped along the way including Fred, BR, Parashooter, and many others. I will update this thread on what I find as my remington brass comes in and BR I'm sure will also share his experience with the Graf cases when he receives them

[butlersrangers]

FWIW - If I ever need to 'thin down' a cartridge shell-holder, I would 'chuck' the lower part in a power drill and 'dress it' with a file, followed with emery cloth, as it spins.

[Parashooter]

Good luck with the file! Most shellholders are thoroughly hardened.

[butlersrangers]

Thanks 'Parashooter', I have not had to tackle thinning a shell-holder, so am unaware of the degree of hardness.

If a file won't cut it, then I would try a 'sharpening stone' or emery cloth laid on a piece of hardwood.

I am taking the liberty of re-posting the SAAMI .30-40 specifications that 'parashooter' gave us in the past on a related thread. It would be worthwhile measuring a Graf .30-40 case to see if it complies with these standards.

(I am not clear in my mind if these are Chamber or Case dimensions)?

[FredC]

I am going to put a link here to tie the threads together.
http://www.kragcollectorsassociation.co ... 962#p38962

The difference in the shoulder distances is a whopping .030 in terms of headspace on a nonrimmed cartridge that could have caused real problems. I am surprised it does not cause more issues today with taking brass from one Krag to another.

Anyone know what serial numbers marked the chamber change? I added another one to the list that had difficulty with the Grafs brass. Funny that my latest barrel from 410854 seems to like Grafs brass.
Zac, I am with the others the shell holders I have dealt with are very hard. Spinning them in a drill with the interrupted cut would seem to be a problem even if yours is not as hard as the ones I have seen. If you happened to have one that was not as hard as the ones we are used to, straight filing in a vice would be better. Sanding done with a flat surface behind the paper is best done with a figure 8 pattern. A little more pressure on the solid side than the cutout side would be appropriate to keep the amount removed reasonably even.