6.5x61 Swedish Exptl?

Just got a new round, marked “6.5x61 SWEDISH EXPERIMENTAL”. CNCS bullet, brass case and primer, headstamp is DWM K 431L K. I’ve known of the round and seen them before, but decided to get one this time. My question…what is it an experimental for? Rifle or MG? Military or commercial? If Swedish, why made in Germany? About when were these made?

Hi Jon
The cartridge was developed in Sweden around 1920 and the rifle was I believe of a Mauser design

This is the commonest of the so-called DWM ‘Swedish’ Experimental series, introduced c1922. It is based on the 6.5x55 case being effectively just a 6mm extended version of that case type. A rimmed equivalent (6.5x61R) also exists…

These are sometimes referred to as “Swedish Experimentals” because an earlier experimental - the 6.5x58 exists with both 'DWM K 431K K ’ hs and also a Swedish military 1916 hs which lends substance to the belief that these were part of a series of Swedish military experiments to replace the 6.5x55 calibre, commencing cWW1. The DWM 431 letters H-M (c1912 - 1933) are referred to as “Swedish” in the DWM case book but what their actual relationship to Sweden is unconfirmed and it may just indicate that they utilised the 6.5x55 ‘Swedish’ case type.

The 6.5x61 was only produced by DWM, it is known with at least six “DWM K 431L K” hs variations either without codes which implies <1925 or with letter date codes “U U” to “G G” (ie 1926 - 1940). It was never produced by DWM with the actual calibre as part of the hs.

Interestingly, even though it is known to have been produced by 1925 (due to the hs style), it was not shown in the 1926 DWM (sporting) catalog. Maybe it was still considered a military experimental at this stage or of no commercial importance. It was later listed in DWM catalogs from 1934 to 1939 and must have made the transition to a sporting calibre.

There has been some confusion re this cartridge in the past. According to the late Phil Sharpe, it was developed after RWS had imported and tested a .256 Newton rifle. He also says in his book “Complete Guide to Handloading”, that RWS, and not DWM developed the 431 L and 431 M, which appears to be completely false.

Many thanks!

Did the 6,5 x 61 ® serve as base for the 5,6 x 61 ® Vom Hofe?

Yes they did Pivi - there is even a 5.6x61R with a “DWM J J K 431M K” hs. Here is the entire history (as far as I know) of the DWM # 431 series:

DWM began a series of cases (#431 series) commencing c1895/1896 all based on the 6.5x55 Swedish case. This case uses a c12.2mm base noticeably larger than the M88 Mauser type.

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 Calibre 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 yes 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)
431I No case is known to have been designated to this number
431J yes c1912 7.5x59 Swedish (W48)
431K yes 1913 6.5x58 Swedish (W44)
431L yes c1922 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 No calibre is known to have been designated to this number
Maybe the 6x61 Hof-Mann Express (W71) based on the 6.5x55
431O No calibre is known to have been designated to this number
Maybe the 6x61R Hof-Mann Express (W72) based on the 6.5x55
431P yes 1934 5.6X61 Vom Hofe (W27) - known with ‘M M’ codes = 1934
431Q No calibre is known to have been designated to this number.
May have been allocated to a Vom Hofe prototype.
431R yes 1934 5.6X61R Vom Hofe (W28) - known with ‘M M’ codes = 1934