8x58R Danish

Loading the 8 x 58R Swedish/Danish Rolling Block

Remington commercialized their rolling block rifle in 1865 and by 1867 it was adopted by Sweden, Norway and Denmark in both rimfire and centrefire versions of the 12.7 x 44R.  However, with the change to the Krag by Denmark in 1889 and Norway in 1894, in 8x58R, existing stocks of Rolling Blocks were converted to the new calibre, to extend their service life.

While the Krag has only one locking lug, it is capable of handling higher pressures than the Rolling Block.  Both the 30-40 Krag (40 – 47,000 psi) and 8x58R (40 – 44,000 psi) are well above the recommended limit for the Rolling Block, which is 25 – 30,000 psi.  This means that loads for the Rolling Block conversions need to be scaled back compared to those used in the Krag in deference both to the design and age of the action.  This is in spite of the new breach block and re-hardened receiver that was part of the conversion.  Most loads available on the internet seem intended for the Krag and should not be used in the Rolling Block. 

An excellent resource is the article “Historical and Experimental Investigations of the Pressure Characteristics of the 8×58 Rimmed Danish Cartridge” and while it says what should not be done, it is sparse on recommended loads.  In fact, the only load that is recommended was a very light, lead bullet and Unique combination.  While I agree that we should not over-stress these old actions, there can be a middle ground, where we produce safe velocities that match original loadings.

The rifle used for this testing shows a receiver date of 1871 and a conversion date of 1895.  Compared to the 12.7 x 44R, the barrel is 4” shorter (33 ¼”) and about 1 lb lighter (8 lb 12 oz).  This has an impact on the recoil experienced compared to the 12.7 x 44R rifle/cartridge but with the loads here, recoil is still mild.

As for the 12.7 x44R, a large number of the 8x58R Danish rifles were imported into Canada around 2014 and most of them are in excellent condition, with pristine bores.  It was a fairly equal split of military and sporterized versions and this means that it is still easy to find a great shooter at a fair price.

While the cartridge was updated in 1908 to a lighter, spitzer bullet, the original loading was very similar to other cartridges of the period, both in terms of bullet weight and energy.  If we stick to that range, we will be at a safe level.

            * compressed BP load

The 8x58R velocity mentioned in Wikipedia is clearly wrong for the original round nose bullet (2460 fps, which is referenced in COTW) and it is unlikely it could be safely achieved regardless of the propellant.

Trying to get to original velocities with blackpowder, is not possible even with compression, since cases are more heavily constructed in the web area and even the walls.  The measured case volumes (filled to the base of the neck with water) are shown in the previous table.  A full, settled, but only slightly compressed load of blackpowder weighed 56 grains and the velocity obtained reflects that.

While the case looks relatively modern, the constraining factor is the action that it is being used in.  The previous table shows a number of loads that were at reasonable velocities for this cartridge and action.  The loads were in Bertram cases, with CCI 200 primers and were less than the specified overall length of 3.07”.  None of the loads listed in the table showed any pressure signs and extracted easily.  The cast bullets (Lyman 323481) weighed 192 gr (#2 alloy) as cast but with a gas-check and lube, they were 195 gr.  They were run through a 0.325” H&I to slightly size them, seat the gas-check and lube them.

The loads for both blackpowder and Triple 7 were settled full case charges, with slight compression.  With Trail Boss, a full case (to the base of the bullet) was 18 gr, which would be a maximum load.  With 5744, the recommendation was that 40% of a full case load is a good starting point.  Hence, 22 gr of 5744 was just above the starting load and it was quite mild.

The results with blackpowder (GOEX FFG) was as expected and is not really recommended.  It is satisfying to see the cloud of smoke and while it is easy to clean the barrel with a rolling block, it is not possible to reach the useful velocities with blackpowder.  If you use blackpowder, be sure to clean the cases with hot soapy water as soon as possible after firing to prevent damage to the brass.  It should be noted that Triple 7, since it does not contain sulphur, is much less corrosive to use and this is an additional reason to recommend it over blackpowder.

Triple 7 was a pleasant surprise in the velocity department.  Due to its higher energy content, Triple 7 did a reasonable job to re-create the original iteration of the 8x58R.  The case was filled to the base of the bullet with only slight compression and this gave an almost 500 fps boost in velocity.  With a bit more settling/compression it would have been possible to improve on the speed but given the lesser case capacity, compared to original brass, it would likely have resulted in higher pressures. 

Trail Boss (if you have any left) was a solid choice with velocities on the mild side and a clean bore.  Even at a full case load Trail Boss topped out at just over 1500 fps for the jacketed bullet (with 18 gr) but it did not shoot as well as the 17 gr load. 

The real winner, for a reduced load, if you are looking for no fouling and higher velocities was 5744.  While the case was only about half full, 5744 burns well under lower pressure conditions and consequently only a few grains of unburned powder remained at the starting load.  Whilst, at 26 gr there was no unburnt powder and the sights were close to being on the mark.  In all likelihood it would

IMR 4064 did not work well with the lead bullet and no load is listed for them but with the jacketed 196 gr soft point, it was a great choice.  Accuracy was good and standard deviation was very low.  Unlike 5744 which is hard to find, 4064 is one of those powders that is always around and the larger kernels help to bulk up in the case.  Careful use of 4064, or related powders like 3031 and 4895, will easily reach 2200 fps, at pressures that the rolling block can handle.  With 40 gr of IMR 4064, it burned clean and the energy level exactly matched the original blackpowder level.  The cases extracted with no effort and the primer pockets were still tight after 8 reloads.  While it may be possible to go to a higher load with IMR 4064 there is no reason to.

Triple 7 can be used to provide the blackpowder experience at a reasonable performance level, while 5744 is a clean shooting reduced load powder.  Mid-range IMR powders converts the 8x58R into a relatively modern 1890s type cartridge.

In summary the 8x58R Danish round is an easy one to load for, with dies and bullets being readily available.  The only caution is that the loads need to match the action it is loaded for.  A 200 gr jacketed bullet at 2000 – 2200 fps generates around 2000 ft-lbs which is in the right energy range for this class of cartridge and will ensure that the rifles keep shooting for years.

Disclaimer

All loads mentioned in this article were safe in the author’s rifle.  However, since it is impossible to know the condition of other rifles and loading techniques, no warranty of suitability is implied or expressed and use of this data is solely at the risk of the user.