Interesting post.

I knew one part from the Jeffery catalogue season 1912-13 and from a paper from Harald Wolf from the Magazine HATARI TIMES N°6.

As owner of a DR of this caliber, a brief note on the cartridges caliber 600 Nitro Express used at the time. That this DR was regulated by Jeffery with 120gr Cordite might be, but I am not so sure if this load was really used.

If you look at the illustration of the cartridge in Jeffery's catalogue, you can see on the picture that the load has been corrected from 120gr Cordite to 100gr Cordite. This would also be more in line with the trend at Jeffery, a company that has always been wary of overpressure with cartridges in tropical areas. Taylor also only mentions in his famous book the classic 110gr and 100gr loads for this cartridge, and nowadays Kynoch also only loads the cartridges 600 Nitro Express with a 110gr Cordite-equivalent load.

I think that at that time the 100gr load was used above all for hunting in Africa and India, a load which, according to Taylor, makes no difference to the stronger 110gr load when hunting. From personal experience I can confirm that a 100gr Cordite-equivalent load is also more comfortable to shoot.