Historical and Experimental Investigations of the Pressure Characteristics of the 8x58 Rimmed Danish Cartridge

By
Galen R. Burgett
Spearfish, South Dakota USA
© February 9, 2009
Don't miss the pressure charts at the bottom of the page...

Acknowledgements

The work on this project would not have been possible but for the generous help and contributions of friends and firearms enthusiasts in the USA and Europe. John Unze provided the Norma factory ammunition and historic Norma literature which form a foundation for much of this work. Dayle Hammock provided a fantastic work space that made life much much easier while I was carrying out the shooting part of the research. Steve Bruns also provided much Norma factory literature and encouragement that kept me upbeat about the work. Don van den Brink also provided direction and encouragement. Thanks to Bill Woodin for his review and suggestions. Also to Bo Casserberg and Ken Buch for many years of wisdom on Swedish firearms and shooting them.

I would also like to thank Jim Ristow of Recreational Software Inc., for putting up with a greenhorn in the ways of pressure and measuring it. John Schaeffer has also been very receptive and offered many helpful suggestions and much information. From Norma in Sweden Torbjörn Lindskog and Åke Nilsson provided important information and encouragement. Also in Sweden, my thanks to Lars-Yngve Ekström for his review and advice. And to all of my collector friends in the USA and Scandinavia who put up with my ravings about the subject. Thank you very much – Tusind Tak!

Introduction to the 8x58R Danish Cartridge

Although generally known to collectors of Scandinavian rifles, the details of the development of and military and commercial use of the 8x58RD(1) cartridge are sparse. Remington Model 67 rolling block rifles in Norway, Sweden, and Denmark were reworked to chamber the cartridge. Norway converted a very small number of rolling blocks to the 8x58R (Hanevik 1998), as was the case in Denmark. Sweden refitted a very large number of rolling blocks and many of these would later be turned into hunting rifles for Swedish civilians. Denmark of course, produced two bolt action rifles chambered for the cartridge, the Model 1889 Krag-Jørgensen military rifle (Nielsen 1990) and a police rifle, the Schultz & Larsen RPLT 42 (Schultz & Larsen 2007). There are one-of-a-kind Mauser trials rifles from Sweden chambered for the 8x58RD (Jones 2003:26). In Figure 1 are shown the M1889 and M1908 cartridges developed in Denmark for the M1889 Krag-Jørgensen.

An issue that has come up in the last few years is the safety of handloaded ammunition made in accordance with information found on the internet and in some recent firearms publications. Some of these loadings are clearly too powerful for either the rolling block or Krag-Jørgensen rifles. Other loadings are simply unknown as pertains to the pressures they generate.

Furthermore, the pressures that these rifles/cartridges were intended to normally operate at and the proof pressures the rifles were tested at, are poorly known. Although we can broadly extrapolate such things from known specifications for similar firearms and cartridges (e.g., the Model 1892 American Krag-Jørgensen), it is always preferable to have some form of reliable historical documentation as a foundation.

From researchers who have examined the original historical documents there are hints of the operating ranges of the original cartridge/rifle combinations. For the Danish Model 1889 K-J, Nielsen (1990:66 ) notes that the original black powder rimfire cartridge for the Model 1867 Danish rolling block operated at about 800 atmospheres, or, 11,760 PSI. When the rolling block rifles in Sweden were rebarreled to 8x58RD we know that they were reworked (new breech block, re-hardened receiver, etc.) to handle the higher pressures of the new cartridge. I believe it will take some archival research in Sweden to ferret out those specifications, but as will be dicussed further on, we can get an idea of what the normal operating pressures were intended to be. Looking at other 19th century military single shot rifle designs there is a wide range of operating pressures given, values from 14,000-28,000 PSI (or CUP).

Nielsen (1990:86 ) tells us that the original compressed black powder cartridge for the Danish Krag-Jørgensen rifles was intended to operate at a maximum pressure of 2,300 atmospheres, or, 33,810 PSI. But, almost from the adoption of the rifle and cartridge, the Danish military worked on improving the cartridge with a smokeless powder loading with spire pointed bullet and adopted such in 1908. The Danish M1908 cartridge was substantially more robust than the original black powder and one would expect that the K-J rifles were built to handle it without problems. Unfortunately, I have as yet to find documentation of the Danish K-J rifle’s smokeless cartridge normal operating pressures and what pressures they were proofed at.

Mallory (1979:20) states that the Danish K-J action is strong enough for an operating pressure of 45,000 CUP, but does not state his source of information for this determination.

Hanevik (1998:336) tells us that the Norwegian Krag-Jørgensen rifle had a normal operating pressure of about 3,500 atmospheres, or, 51,450 PSI. But, this was for the Norwegian version of the 6.5x55 cartridge and there are some design differences between the Danish and Norwegian K-J rifles. For the American Krag-Jørgensen rifles there are various operating pressures given in the firearms literature ranging from 38,000-48,000 PSI (or CUP in some sources).

It is doubtful that we will ever know the exact pressure ranges and limits of these old military rifles and cartridges. Pressure testing of cartridges and firearms in the late 19th century was still an emergent technology and science. Values given for pressures specified in design development or realized during testing probably had considerable error factors, so there may be several thousand actual PSI difference between the true pressure and the measurement given or recorded. Nevertheless I believe a safe range of loadings can be developed that will also not cause undue stress and wear on the old rifles (see Footnote 2 for a discussion of pressure measurement).

Norma Factory Ammo: History and Documentation

So, let me begin with the Norma factory documents that provide the most information and which I hope provide the most accurate historical understanding of the 20th century commercial/civilian 8x58RD cartridges. Commercial cartridges were also loaded by Dansk Ammunitionsfabrik A/S in Otterup, Denmark, and DWM and RWS in Germany, but I have had little success in gathering primary documentation on those companies’ loadings. 8x58RD also appears to have been loaded by Remington late in World War I, but I have as yet found documentation for that ammunition. There may have well been other commercial ammunition makers in Sweden, Norway, or other countries that produced 8x58RD, but there have been no examples I have seen as yet.

Norma possibly began production and sales of civilian 8x58RD ammunition before WW II, but I have not located documents yet that show that. The earliest mention (see Figure 3) of commercial Norma 8x58RD I have found so far is in a 1947 issue of Svensk Jakt. Svensk Jakt is the journal of the Svenska Jägareförbundets, or, Swedish Hunters Association. As can be seen in Figures 3 and 4, the advertisement shows that the 8x58R ammunition is for the Remington rifle, which in Sweden is almost always understood to mean the Model 67/89 rolling block rifle. By 1951, Norma had expanded their commercial cartridge line as shown in Figure 4. The brief history of Norma in the Norma Reloading Manual (2004) does not mention the cartridge.

Norma began reloading salvaged 6.5x55 military cartridges in 1914 (Norma 2004:14) for sale to civilian shooters. It is plausible that salvaged 8x58RD military cases were also reloaded, but this is unknown(see Footnote 3). The earliest dated American advertisement for Norma 8x58RD that I have comes from a 1949 American Rifleman magazine (see Figure 5). The earliest box of ammunition that I have is dated 1953, an example is shown in Figure 2. As can be seen in Figure 2, the label is clearly marked for the Model 67/89 Remington type rolling block. A Norma factory catalog page that dates to 1953/54 is shown in Figure 6. With five types and weights of bullets, the 8x58RD line up was impressive ranging from a 159 grain bullet to a big 227gr soft point.

The Swedish/European market 10-round boxes were sometimes marked for either the model 67/89 rolling block or the Danish Krag. It does not appear that the practice continued after the introduction of a new package design which dates to the late 1950s or early 1960s (see Figure 7, box on far right of photo). Also of note is that in the factory cartridge specifications literature, the difference between rolling block and Krag-Jørgensen loads is not specified.

The early 1950s was a time of great development and experimentation at Norma and the company was making major moves into the American market. An English language 1956 dated brochure with cartridge listings touts the new improved powders and the extensive listing of American cartridges demonstrates the desire to be a player in the American market. But, of specific interest for our purposes, is the 8x58RD listings from several Norma brochures I have examined, as shown in Figures 8, 9, 10.

Note that in the earliest dated load listing the powder is stated to be Norma 103. I have been unable to find any information on the production span of this powder, but it appears to have been replaced by the 203 powder sometime in the late 1950s. Figure 11 shows a disassembled cartridge from a 1950s period Norma box. Packed in the case, underneath the 196gr soft point bullet was 44.4 grains of a square cut flake powder, which I would guess is Norma 103.

I have contacted Åke Nilsson at Norma technical support about the production dates for the Norma powders, but have not received an answer as yet. Just a side note, Norma powders are actually manufactured by Bofors in cooperation with Norma research and development. Mr. Nilsson did state that the practice of stamping a very small “NP” on the primer was ended about 1963, so there is a before and after date that can be used in determining the approximate age of Norma factory ammo.

Of specific interest in the Norma factory specifications are the pressure figures given. Although in the factory listings these pressures are given as atmospheres and PSI, the instrumentation used was of copper crusher type, so these values may be more appropriately called CUP, although that is an American convention. In correspondence with Åke Nilsson of Norma technical support, I was informed that the pressure testing done by Norma during the 1950s and 1960s was by the copper crusher method. Whether this was the same as the CIP protocol of the time or a Norma specific protocol, he did not relate. Sweden is not a member nation of CIP, but it is likely that Norma ammunition and testing procedures meet or exceed CIP standards (see Footnote 4).

To summarize those pressure values from the charts we have, by year, the following:

Year Bullet Weight Norma Pressure (copper crusher) Norma Velocity (fps)
1956 two 196 gr bullet loadings 28,670 2,230
1956 196 gr 29,110 2,300
post-1958 159 gr bullet 28,660 2,477
post-1958 196 gr 26,460 2,231
post-1958 198 gr 23,030 2,290
post-1960 196 gr 26,500 2,230


One thing that stands out from examining this literature is that the number of Norma factory loads shows a reduction in the number of loads listed, from the five listed in ca.1953 to four loads, to three, and then just one in the latest dated table.

But, to the subject at hand, pressure. In our modern perspective these pressures seem quite low and indeed they are, regardless of how they were measured. This, to me, indicates that Norma had experimentally determined or was privy to information from the Carl Gustafs Gevärsfaktori regarding the pressure handling capabilities of the Swedish m/67-89 rolling block. It also indicates that although Norma marked its early production 8x58RD relative to m/67-89 or Danish Krag, that perhaps there was little if any difference between the amounts of powder used for these loads. In summary, I believe I have presented the basic information about the Norma factory 8x58RD loads and their pressure measurements. With the literature I have examined, several facts stand out.

First, no Norma 8x58RD loads exceeded 30,000 PSI(CUP) as measured by them. Average pressure was 27,532 PSI (n=8). Second, muzzle velocities ranged from 2230-2477 fps with an average of 2287 fps (n=8). Finally, the number of 8x58RD loads offered by Norma declines steadily through the 1950s and 1960s, indicating the declining popularity and profitability of the cartridge. In The Norma Gunbug’s Guide, No. 61, there are no 8x58RD loads listed. My best guess is that Norma ended production of the 8x58RD in the early or mid 1960s. I have asked Åke Nilsson when production ended, but as yet, have not received an answer (see Footnote 5).

Non-Factory Loadings from American Hand Loading Literature

Now we come to the thorniest part of the 8x58RD saga; the information published in American cartridge and reloading books. The earliest American mention I have found for reloading the 8x58RD cartridge is in the 41st Edition of the Lyman Ammunition Reloading Hand Book (Lyman 1957: 110). In Figure 12 I have scanned the important information from that publication. In the Lyman printing, it is unclear who developed this loading data, but it does acknowledge that the “velocities and pressures given below have been taken with standard European pressure and velocity equipment”(Lyman 1957:109). Significantly, an asterisked footnote tells us that the 8x58RD data is a “load intended for Danish Krag rifles or other arms of corresponding strength“(Lyman 1957:110) Also of note is the specification of Hercules HiVel 2 powder for two of the loads. So, the question arises, where was this load data developed? It states Norma cases and bullets were used and velocity and pressure values were obtained with facilities meeting European standards. But, where did this data actually come from?

Well, fortunately, that is an easy question to answer. It came from, The Norma Gunbug’s Guide (1957,1959). The Gunbug’s Guide was first published in 1957 (Norma 2004:18) which of course is the same year as the Lyman Hand Book. I do not have a copy of the 1957 edition, but I do have a copy of the No. 59 Norma Gunbug’s Guide and on the last page(see Figure 13) is the exact same set of loads for the 8x58RD that was published in the Lyman hand book. In fact, the load listings for all the Norma brass and bullet loads in both publications are identical to the Lyman hand book. So, it would appear that Lyman obtained this listing from Norma in some manner, but did not directly credit Norma with providing it. On the first page of the Gunbug’s Guide, Nils Kvale, the renowned head of the Norma Ballistics Laboratory, describes and explains that the loads were all developed in the Norma labs.

Interesting that; in any case, there is something odd about the 8x58RD load listing. In the Norma chart, there are numerous attribute listings that are blank. These missing attributes or values are as follows:
This is quite odd. First, this is the only rifle cartridge in the entire listing that is missing all those attributes. Particularly interesting is that the three loads listed have no Norma index number which indicates these are not Norma production loads. Every other rifle load has corresponding Norma and American powders, except the 8x58RD. And adding to the puzzlement, is that only muzzle velocity is listed. Why is the 8x58RD load the only one presented like this? The Norma listing also omits the warning found in the Lyman version that these loads are only intended for the Danish K-J rifle. Why? I suspect that at this time, i.e., 1958-59 and previous years, Norma was not exporting 8x58RD ammunition to the USA. By 1961 Norma dropped all 8x58RD loading information from the Gunbug’s Guide. As we have already seen in previous Norma 8x58RD load listings, none of Norma’s domestic 8x58RD production comes close to the pressures listed for the loads using American powder. In other words, there are no known Swedish factory equivalents for the American loads. Did Norma just not want to have to explain the differences between the Swedish and American loads? I also will repeat a point made previously, that is, these are not Norma factory production loads, they may have been developed by Norma in their ballistics lab, but they are not factory production loads.

Beginning in 1965 and continuing through the present, the 11 editions of Cartridges of the World: A Complete and Illustrated Reference for Over 1500 Cartridges (Barnes) have been a standard reference for American firearms collectors, shooters, and handloaders. Frank Barnes did a tremendous amount of work to gather all the information together and then compile it and has been rightfully commended for this effort (Barnes died in 1992 and the editor of the book since then has been Stan Skinner). Nevertheless, as will be demonstrated, the treatment of the 8x58RD cartridge leaves much to be desired. A scan of the full CotW 8x58RD entry is seen in Figure 14.

So let us examine the entry.

Where Barnes is completely off base is in his description of 8x58RD Norma sporting ammunition. The information given in his description is simply wrong. The Norma production 8x58RD ammunition, as we have seen in previous discussion, never came close to the velocities given in Barnes’ description. In the load table in the description these velocities are given as being from factory loads and the accompanying hand loading data is said to duplicate factory loads. Again, this is wrong. Where did Barnes get this information? Well, it is not difficult to see that his load data, for the most part, is nearly the same as that found in the Lyman hand book and The Norma Gunbug’s Guide No. 59. The bullet weights and velocities are identical. What differs is the substitution of IMR 4895 powder for the HiVel 2. HiVel 2 was discontinued in 1965. The other difference is the most critical and probably dangerous one. The grains of IMR 4895 for the respective bullets are given as 54 and 54.5. The HiVel 2 grains were given as 52.4 and 52.9. Barnes simply substituted the IMR 4895 for the obsolete HiVel 2 and adjusted the powder quantity.

To summarize the previous discussion, Barnes mistakenly used load data from hand loading guides that is not derived from Norma factory production or development and bears no resemblance to the actual Norma factory ammo information that has been documented. Barnes further complicated the picture by substituting a powder type and powder weights that had not been tested by anyone, as far as I know. While we could quibble and argue that the loads listed in The Norma Gunbug’s Guide are factory loads because they were published in a Norma document, the simple fact is they are not. They were developed in the Norma ballistics laboratory, but were never in production. Particularly baffling is the oddity of that load when compared to every other rifle cartridge in that guide. It is missing substantial amounts of data that the other loads are not. Why the 8x58RD loadings were treated differently by the Norma lab in their presentation, compared to the other loads, is unknown, and perhaps unknowable. Frank Barnes may have had decades of experience and knowledge, but in this situation he simply dropped the ball.

Into the Real World

I wanted to add some real world shooting experience and it was with the generous help of collector friends that I was able to obtain a quantity of Norma factory 8x58RD to do so with. In order to carry out such tests, I obtained a Pressure Trace II strain gage pressure measuring unit and a CED M2 chronograph (Figure 15). I will not go into the details of the Pressure Trace II technology and the science behind it and refer the reader to the RSI website for further information on this measuring device. www.shootingsoftware.com

The Pressure Trace technology has been in use, privately and commercially, for several years and has a good reputation for reliability and accuracy.

Of course, pressure and velocity were the measures I was primarily after, but conveniently the Pressure Trace II unit and software provides a statistical breakdown of each shot as well as an averaged summary of the string as a whole. Three interesting results, Efficiency Percent, Area, and Rise are also given and these statistically derived values can be quite important in determining what the load is doing internally and externally. A brief description of Percent Efficiency and Area are given on the graphs that follow and Rise is described as,

“The rise time is calculated as the time, in microseconds, it takes for the pressure to rise from 25% of the peak value to 75% of the peak value. This can be taken as an indication of the ‘speed’ of the powder in use.” ( Pressure Trace II Operating Manual 2008)

I attached strain gages to two rifles. The first rifle was a Schultz & Larsen RPLT 42 police carbine shown in Figure 16. The second rifle was a Danish Krag-Jørgensen M89/24 Infantry carbine.

I had fired approximately 300 rounds through both rifles before with low intensity cast bullet loads and had encountered no mechanical problems and no indicators of excessive headspace. It turned out that the S&L rifle would be used for the pressure testing and the Krag-Jørgensen was kept in reserve.

Thanks to another good friend, I was able to set up my outfit within a large steel building and to shoot out of the back overhead door to a backstop approximately 100 yards away. With all the electronic technology; i.e., Pressure Trace II and Dell laptop computer, I just did not want this sizable investment exposed to the sunlight and dust bearing wind of the great outdoors.

Shooting began after some preliminary learning with some mild handloads so I would know how to use the technology without wasting the factory ammo. After that was achieved, I began tests with the Norma “kal. 8mm. mod. 67/89, Langa helmantlade, Kulvikt 12,7 gr.” cartridges (see Figure 2). This of course is the rolling block ammo with a full metal jacket roundnose bullet weighing 196 grains. The box index number was Nr. 640 and the date on the box was March 1953. Figure 17 shows a graph of the results of a five shot string. Average pressure was 20,467 PSI and average velocity was 1,764 FPS. The shots show a nice uniform pressure curve. The rise time on this this shot string averaged 370 microseconds, which is a relatively slow burning powder. As is evident, pressures and velocities are relatively low and probably not surprising, given that these are specific rolling block cartridges. Also, while it is impossible to determine the age effects on the ammo, which is at least 55 years old, and that may have had some effect. But, this was also a sealed box, the cartridges looked brand new, and there were no external signs of deterioration, so perhaps age did not have much effect at all.

The second string fired was six Norma factory 196gr loads. This box was unsealed, marked Remington, as well as, “kal. 8mmm. Mod. 67/89” and the bullets were of the type with a widely exposed lead tip. These Norma bullets precede the famed Norma Alaska bullet which has much less lead exposed and I believe a different ogive. The best guess of the date of manufacture for these cartridges is between 1953-1963. Figure 18 shows the graph and statistical summary of that string, averages were: 23,353 PSI and 2,058 FPS. I fired six rounds of this cartridge because the third shot, T3 (Trace 3) on the graph shows a bizarre pressure curve. When I extracted the spent case, I found it had split longitudinally on the case body. Why this case split is unknown, but age/deteriorating powder/primer are likely suspects. The other five shots show that nice uniform pressure curve evidenced in the first shot string. Average rise indicates a powder similar in burning “speed” as the first shot string, and the pressures and velocities seem to indicate a little more powder charge.

Shot string three (Figure 19) was five cartridges from a box clearly marked “Danish Krag” and the results are definitely different than the first two shot strings. This box was unsealed and I had disassembled one cartridge to measure the powder charge (see Figure 11). These rounds were topped with the wide lead tip 196gr bullet and as on all previous cartridges, the primer was stamped with the small “NP” trade mark. Averages for this shot string were, 25,374 PSI and 2,143 FPS, showing a bit more “oomph” than the previously fired cartridges. The average rise, at 230 microseconds, indicates an ever so slightly faster burning powder than evidenced in the previous shot strings. Shot string four (see Figure #) was also five cartridges from the box marked “8mm Danish Krag”. This string is statistically identical to shot string three, not surpisingly.

The final shot string (see Figure #20) of Norma factory 8x58RD came from a much more modern design box and was loaded with recognizable Norma Alaska 196gr bullets. The box did not specify the firearm type. The primers on this ammo were not marked with the tiny “NP”, but in correspondence with Åke Nilsson, he informed me that this practice ended sometime in or around 1963. This shot string was the “hottest” of the factory loads, but statistically is identical to the two previous shot strings.

So, to summarize, there appears to be a clear ballistic differentiation between Norma factory ammunition marked for use in either the rolling block or the Danish Krag-Jørgensen. It is not a huge differentiation, but it is there. However, it appears that by the late 1950s or early 1960s, Norma was not making this differentiation anymore, and the ammunition was loaded to the slightly higher pressures and velocities. Given our understanding of the Swedish rolling block Model 67/89 and extrapolating from other similar historic period single shot military rifles, the practical operating pressure for the rifle appears to be around 25,000 PSI. I believe we can possibly conclude that the Norma technicians knew something about the rolling blocks and their pressure limits that they did not mention in the Norma publications. To iterate a previous observation, the pressure curves on all of the Norma factory ammo were quite smooth and uniform. Of course, the visual aspect of the pressure curves is due to the scales used on the graph, but the statistics show the same thing. I believe this indicates that the ammo was in relatively good condition, with the exception of the split case, and that age had not taken a great toll on its operating capabilities.

Before summarizing this project, I would like to show two more pressure graphs done during the testing. The first, Figure 21, shows a single trace with a pressure of 44,432 PSI and a velocity of 2,339 FPS. There is only one shot trace because this round showed explicit pressure signs and caused the bolt on my Schultz & Larsen RPLT 42 to be quite stiff and difficult to open. No sense in being stupid when things start acting like that.

The last graph is what I call my plinking load for use in both rolling blocks and K-J rifles. No it is not a supersonic moose annihilator, but why should it be? It is a fun load and will let my treasured Scandinavian rifles shoot on for many years to come. The bullet is a 190gr gas checked cast bullet from Mt. Baldy Bullets in Cody, WY. The powder is the great old standard for turn of the 19th century rifle blackpowder and smokeless cartridges, 12gr of Unique. One of my future projects with the Pressure Trace II and chronograph is to work the Unique powder up grain by grain to about 15gr and see what happens. If the measured pressure warrants and accuracy is acceptable a grain or two more of Unique might be added to the recipe.

Summary and Conclusions

A documented source for information on the operating pressure of the Swedish Model 67/89 rolling block has not come to light yet. Second, the historic literature, i.e., phamphlets, tables, books, from the Norma factory, document that Norma was rating their 8x58RD loads at an average of 27,532 X (I use X here since the actual measurement is probably a copper crusher type). The actual PSI that these old cartridges operate(d) at, could be several thousand PSI above or below that average pressure. I also demonstrated that 8x58RD loads in American publications are at the least, suspect and should be approached cautiously. The loads found in Cartridges of the World, in my opinion shouldn’t be approached at all. The assertion in CotW that those loads duplicate factory specifications has been shown to be untrue. There are no known Norma factory 8x58RD loads that even come close to the quantities of powder used and the velocities reported. If Norma factory information from a later period, such as, 1975-2000, is discovered that shows Norma factory ammunition being loaded to those specifications than of course, my conclusions are rendered invalid. But, the lack of documents and publications detailing 8x58RD specifications after ca. 1965, would indicate that Norma stopped production of the cartridge at that time. I was able to examine Norma factory literature, i.e., catalogs, American dealers price lists, and Gunbug’s Guides, ranging from 1959 to 1980, and found that after about 1961-65 there is no mention of the 8x58RD cartridge. I have asked Åke Nilsson at Norma technical support for his help in determining when production did stop and hope he can provide answers.

Third, my testing of the pressures generated by original Norma factory ammunition show PSI readings ranging from 19,567-26,813 PSI, and shot-string pressure averages ranging from 20,467-25,890 PSI.

Finally, the condition of our rifles should be our utmost concern, both as we receive them and maintain them. I would suspect most of us our pretty faithful in cleaning, lubricating, and repairing our rifles, but they have decades, sometimes a century or more, of accumulated time and use and we must really keep on the lookout for signs of stress and structural failure. Headspacing is critical for assessing shootability and maintaining it. Unfortunately, our knowledge of headspace specifications in the old Norse rifles is virtually nonexistent, but I am working on that also and perhaps I and others can change that situation.

Footnotes

Footnote 1- I refer to the 8x58R Danish cartridge as 8x58RD because the 8x58R Sauer cartridge is sometimes confused with it.
Footnote 2- A slight, but pertinent divergence here. The pressure values in the Norma literature are given as PSI (pounds per square inch) and the European convention of atm. (atmospheres). As has been discussed in any good reloading manual and numerous articles in books and shooting magazines for decades, that before the late 1960s, all pressures were measured indirectly, mainly by a copper crusher type of instrumentation. The American standards developed by SAAMI/ANSI refer to the figures derived from copper crusher as CUP. Although it seems almost elementary to have to discuss this, it is very important to understand the copper crusher measures are indirect and relative measurements of pressure and may or may not represent the actual PSI. It must also be kept in mind that although most copper crusher methods of testing either by SAAMI or the European CIP and the various ammunition and reloading component companies, while supposedly rigorous and standardized as to protocol, are not easily, if at all, comparable to one another. Testing of identical loads by different laboratories often results in pressure values that differ from one another, sometimes by considerable amounts. So, what we are dealing with when discussing pressures is a quite relative and possibly broad range of results and we should never assume that these measures are definite universal values. But, over the decades the laboratories, physicists, and ballisticians have developed a level of confidence in their testing protocols and can recognize when things are operating within a normal and usually safe range of pressures. The sheer mass of scientific literature concerning the measurement of pressure is mind boggling, but a basic and useful understanding can be derived from such references as Bramwell(), Brownell (), Sharpe() and the better reloading manuals.

Footnote 3- The practice of reloading salvaged cartridges, obtained either from the military activities or civilian shooting clubs, was a common practice throughout Scandinavia. Dansk Ammunitionsfabrik A/S also reloaded salvaged military 8x58RD, and other calibers, beginning the practice around 1911. The practice continued at least until the late 1940s.

Footnote 4- Some more interesting background information. I looked through old copies of the Shooter’s Bible, Nos. 40, 41, 50, 59, and 60; and old copies of The Gun Digest editions, covering a range of dates from 1949-1982. In these volumes, there was no listing for any 8x58RD ammunition, whether from Norma or any other manufacturer. Now, this certainly does not mean that Norma 8x58RD ammunition was not imported to the USA, but it does indicate there was not much interest or demand for it. This will be discussed further on in this research.

References

Print Sources:

Web Sites:

Figures 1-23 for text references


Figure 1. Danish M1889, 1915 dated cartridge(left) and M1908, 1918 dated cartridge loaded at Hærens Laboratorium in Copenhagen.


Figure 2. Sealed box of 8x58RD ammunition. The bullet was a full metal jacket roundnose of 196 grain.
Cartridge was intended for the Swedish 67/89 rolling block rifle.


Figure 3. Advertisement for Norma ammunition in 1947 issue of Svensk Jakt magazine.


Figure 4. Advertisement for Norma ammunition in 1951 issue of Svensk Jakt magazine.


Figure 5. Advertisement for Norma ammo including 8x58RD from 1949 American Rifleman.
Interestingly, the American market ammunition appears to come mostly in 20 round boxes.
Swedish market boxes of this time period were 10 rounds.


Figure 6. Page from Norma catalog dating to circa 1953.


Figure 7. Norma packages showing differentiation between rolling block and Krag-Jørgensen cartridges.
The first two packages from the left are dated 1959 and 1953. The two packages on the right are not dated,
but the end package is of a design that came into use in the early 1960s.


Figure 8. Table listing of cartridge loads from 1956 Norma factory brochure.


Figure 9. Table listing rom Norma factory loading data booklet. Exact date is unknown,
but it appears to have been published after 1958.


Figure 10. Cartridge load listing from Norma factory booklet. Exact date is unknown,
but is believed to be ca. 1964-1968.


Figure 11. Disassembled cartridge from undated Norma box.
Note the box is clearly marked "8mm. Danish Krag". The index number is Nr. 764.
Bullet is the old style 203 grain soft point.


Figure 12. Page 110 from the Lyman Ammunition Reloading Hand Book (1957).


Figure 13. 8x58RD loading data from Norma Gunbugs Guide, No.59(1959).


Figure 14. Scan of 8x58RD description from Cartridges of the World (2006).


Figure 15. Pressure Trace II pressure measuring unit and accessories.


Figure 16. Schultz & Larsen RPLT 42 rifle with strain gage attached.


Figure 17. Shot-string #1, five rounds of Norma factory full metal jacket 196 gr bullet loads.


Figure 18. Shot-string #2, Norma factory rounds, 196 gr old style soft point bullet.


Figure 19. Shot-string #3, Norma factory loads marked "Danish Krag" on box label.


Figure 20. Shot-string #5, from newest design box with 196 gr Alaska bullets and no "NP" stamped on primer.


Figure 22. One shot trace, stopped because of pressure signs.


Figure 23. Plinking load suitable for rolling blocks and Krag-Jørgensen rifles.


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