This is the first of the so called DWM case #431 ‘Swedish Experimental’ series (see article). Only known with "DWM K 431H K " hs without letter date codes which implies manufacture prior to 1925. Listed sometimes as 7.4x59 but commonly referred to as 7.2x59.
This is a very rare cartridge and I personally only know of four examples (??) confirmed as existing; two in the Woodin Laboratory Collection, one from Nils Olsson and one from Austria. There are likely to be others but I suspect not that many.
An undated but c1912 DWM Factory drawing of this case type exists (see images). This drawing is titled “Versuchs-Munition für das Schwedische Gewehr Kal. 7,2mm.” (“Experimental ammunition for the Swedish rifle Kal. 7.2mm.”). This is where the “Swedish Experimental” title is probably derived.
*************** DWM case #431 Series
DWM began a series of cases (#431 series) commencing c1895/1896 based on the 6.5x55 Swedish case (SC64). This case uses a c12.2mm base noticeably larger than the M88 Mauser type.
The first of the DWM431 series was the 6.5x55 Swedish M94 military caliber (case #431). All lettered sub-series of this series utilised the same base as the original 6.5x55 case (c12.2mm base). The letters H-M (c1912 - 1933) are referred to as “Swedish” in the DWM case book but what their actual relationship to Sweden is unconfirmed. It is believed that they were originally an experimental military series possibly designed to replace the 6.5x55. These cases were all unique types, some of which were listed commercially.
A DWM factory drawing of the case #431K is known dated 30 August 1913 helps to establish the introduction dates of these cartridges. The full list is as follows:
case# exists Date Caliber and Notes
431 1896 6.5x55 Krag-Jorgensen M94
431A 1896 6.5x55 Rottweil - probably loaded with Rottweil powder
431B 1896 6.5x55
431C yes 1896 6.5x55 Mauser M96 - common commercial 6.5x55 cartridge
431D yes 6.5x55 Luxembourg - Military loading for Luxembourg
431E ? 6.5x55 Swedish
431F yes 1905 6.5x55 Swedish M05
431G 6.5x55 for SFM - loading for the French Company SFM.
431H yes c1912 7.2x59 Swedish (W47)
(Note Germans do not use the letter “I” - ie. No 431I used)
431J yes c1912 7.5x59 Swedish (W48)
431K yes 1913 6.5x58 Swedish (W44)
431L yes c1924 6.5x61 Swedish -commercial use listed till at least 1939 (W45)
431M yes 1933 6.5x61R Swedish - rimmed 431L (W46) - ‘N N’ codes= 1933
431N yes c1933 No case is known to have been designated to this number
May be the 6x61 Hof-Mann Express (W71) based on the 6.5x61
431O yes c1933 No case is known to have been designated to this number
Maybe the 6x61R Hof-Mann Express (W72) based on the 6.5x61R
431P yes 1937 5.6X61 Vom Hofe (W27) - First date code ‘M M’ = 1953
431Q ? No case is known to have been designated to this number.
May have been allocated to another Vom Hofe prototype.
431R yes 1937 5.6X61R Vom Hofe (W28) - First date code ‘M M’ = 1953
6.5x61 Swedish Experimental