Rhodes,
Sorry, but I have no cameras of any kind; don't like cameras of any kind. More importantly, I have no ideas how to post pictures online, something I have not yet done, so I can't post pictures.
The .500/.416 was designed by Kreighoff, specifically for double rifles. It gives same performance as the outstanding .416 Rigby cartridge, but on a rimmed cartridge of less breech pressure. If you like the .375 H & H, you will love the .416 Rigby!
Kamilgroi and Sarg,
The original, and best, Simson guns were pre WWII Simsons. Simson family was Jewish, so, of course, the Nazis seized the firm in 1939 (early hate toward the Jews), when the company became BSW, . Post war Simsons had no connection to original Simson family and original guns at all. These East German guns were stamped Merkel and Simson, but were all same guns of same design. I think that Brown's conversion was with one of the early pre WWII better quality guns, though the post war Simsons were strong well made guns, but the stocks were far from good; often splitting and breaking easily.