1898 .30-40 vs 1894 6.5x55 for action stregnth?

[Rapidrob]

I have two Krag rifles in the collection. A 1898 .30-40 made in 1903 and Norwegian 1894 made in 1914 in 6.5x55.
The chamber pressures between the two cartridges are close to 10,000 PSI different with the issued military ball loading's.
I know Swedish steel would have been used by Norway as it was the finest steel in the world for many decades.
Is the Krag action strong enough by its design to handle the 6.5x55 chamber pressure alone with it's one major locking lug?
Since the rifles do exist and were issued during the same time period, one would assume either chambering is safe for the rifles action.
Were other factors done to the Norwegian rifles such as special hardening or stronger alloys?
Thanks for any helpful info.

[Whig]

Are you asking theoretically since the 6.5mm cartridge is close to .25 caliber compared to the .30-40 Krag round? Thinking or re-barreling the Krag rifle? The original military 6.5x55 bullet was 156 grains compared to the .30 US at 200 grains. I don't know of a head-to-head comparison since the actions and chambers are different with the different size cases.

[Dick Hosmer]

Cannot comment on steel quality or method of hardening, etc. between the two actions, but one salient point that I've always heard is that the Norwegian action was lapped, or otherwise machined so that the safety rib also bears on the receiver, providing almost double the locking surface in contact at discharge.

And then, there is always the test performed on a US Krag with front lug machined off, using JUST the safety lug, that took an un-Godly amount of pressure (like 100,000 PSI, IIRC) before letting go. But, to be safe, I'd stick to recommended pressure levels - if you want to shoot 6.5x55 do it in the Norwegian, or, maybe better yet a Swedish Mauser?

[Rapidrob]

I just wanted the info. I'm not converting either rifle.
My question is "how strong is the Krag action?"
With 100 K PSI on the bolt handle with the lug milled off,that answers my question.

[FredC]

I understand that some of the European Krag bolts lock on both the locking lug and the guide rib. With the bolt handle as a safety and assuming yours also is locking on the guide rib your Norwegian Krag should be the stronger of the two. If the headspace is correct your Krag should be safe with standard 6.5X55 ammo.
Many years ago I had a 6.5X55 Swedish Mauser and used Norma ammo to till I had enough cases to reload. I would assume that most 6.5 ammo is loaded moderately for older actions and if there is ammo loaded out there for modern guns and higher pressure it would be so marked like Plus P ammo for 38 pistols.

Probably not see the next comment by Bernt.

[Bernt]

Swedish steel was good, no doubt. But was it actually the worlds finest? or is it just one more of the internet myths? I've seen it repeated on internet forums, but not in periode litterature about rifle production.
Haneviks book about the Norwegian Krag states that only the best steel was used, but most were bought from Germany and Austria. Some Swedish steel was used for barrels.

In Europe, modern 6,5x55 ammunition is mainly made for modern actions and rarely bare any warnings of use in old milsurps. Modern cartriges can have a max chamber pressure of 3800 BAR = 55114 PSI. Since neither Norway or Sweden are members of CIP, this pressure standard was not set with old milsurps in mind. In the USA, it is normal to load ammo on the low side, because of fear of law suits. This is not the case in Europe. Many European countries have proof laws, that demand any firearm sold on the civillian marked to be proof tested for strength. Norway and Sweden have no such laws. All we know is that the rifles were proofed when new, 100 + years ago. A lot of guys seems to shoot all kinds of commercial 6,5x55 through their milsurps without any trouble, but remember, this is 100 year old rifles, and who knows what (ab)use they have seen.

In the Swedish Amkat 1990 edition (the Swedish armys ammo manual), max pressure in military 6,5x55 ammo is 330 MPa = 3300 BAR = 47862 PSI.

The Norwegian shooting associations regulations, 2023 / 2024 edition, set 3300 BAR = 47862 as max pressure in Krag ammo, but 3800 BAR = 55114 PSI in Sauer and Mauser (in Norway that means M98 actions).

P.S: In this article from 1992, Raufoss states 350 MPa = 3500 BAR = 50763 PSI as max pressure in the Krag. The shooting association is more conservative to give the old Krags some more slack.

Amkat 1990.jpg (110.3 KiB) Viewed 1126 times

skytterboka 23 - 24.png (231.77 KiB) Viewed 1126 times

Maxtrykk1 (1).jpg (757.73 KiB) Viewed 1114 times

[Dick Hosmer]

I just wanted the info. I'm not converting either rifle.
My question is "how strong is the Krag action?"
With 100 K PSI on the bolt handle with the lug milled off,that answers my question.

To clarify, and it is certainly there as a last resort, but the bolt handle was not what was used for the test I'm recalling (which is somewhere in our archives) but the guide rib or so-called safety lug. The bolt handle does sit in a rather deep notch, but, AFAIK, it was never meant to bear any load.

[psteinmayer]

The test Dick is referring to was performed many years ago by Michael Petrov... and demonstrated that the US Krag was actually incredibly strong. As Dick said... it took a LOT to cause a failure!

https://www.doublegunshop.com/forums/ub ... ber=211013

Rest assured, I wouldn't go and purposely remove the locking lug... but that guide rib provides quite a strong backup safety, should that single lug crack!

[scottz63]

Wow! Who needs locking lugs anyways? LOL!

[butlersrangers]

U.S. Krags and many Norwegian & Danish Krags were built over 120 years ago. They were built with early metallurgy.

They are products of a 'developmental era'.
The World of military and sporting arms shifted from black powder cartridges, with large caliber, heavy Lead projectiles, to 'smokeless' powder' necked cartridges, with high pressures, driving small caliber, light, jacketed projectiles, to high velocities.

There were many 'growing pains' and obstacles to overcome back in this transitional period.
The Krag actions, (Danish, U.S. and Norwegian), were strong enough for the working pressures of their adopted cartridges.
The Krag rifles and carbines were carefully manufactured at quality armories. A lot of "safety" was engineered into the Krag-Jorgensen design, so that some failures might destroy the arm, but not kill the operator!

Danish and Norwegian Krags were produced longer than U.S. models, so their steels underwent some improvements during the periods of manufacture.
Krags appear to have an enviable Safety Record. A large part of this is, likely, because operators observed cartridge pressure limitations.

Cartridge case failure and how an action handles escaping high pressure gases, has a lot to do with shooter safety.
The rim or flange of the .30-40 and 8mm Danish cartridges serves a role in limiting the gases, from a failed cartridge case, from entering the Krag action.

The rimless 6.5X55mm Norwegian cartridge case does not have a flange to act as a bonus gas seal. Also, there is some 'hot' 6.5X55mm commercial ammunition, that has been manufactured, which exceeds the intended pressures for the Norwegian Krag.

Over a long period of time, some firearms have been subjected to forces, like wear, heat, fire, chemicals, or mechanical abuses, that have compromised strength and possibly introduced metal fatigue or embrittlement.

It is important to visually inspect an arm and 'fired' cartridge cases to look for clues that things are quite proper and not abnormal.
"Know Your Gun and Ammunition".
Use factory ammunition and reloads, that comply with original Krag pressure standards.

If you want a magnum ... buy a magnum ... not a Krag.