This is described as the 11.5x36R Montenegrin Gasser that was used in a heavy 6-shot Gasser system revolver. This cartridge was listed in the 1909 SFM catalogue as the “11.5mm Montenegrin Gasser”. The ‘standard’ 11.3m Gasser M.1870 revolver has a tapered case, whereas this was listed with a distinctive neck. White & Munhall on p.68 mentions a description of a Montenegrin Revolver that fired a bottlenecked cartridge that was manufactured in Belgium and was described in Hugh Pollard’s History of Firearms, published in 1926. This was only ever listed in the SFM catalogue and no other manufacturer makes mention of this 11,5mm round. There is a lot of confusion regarding the 11,3mm Gasser and in Mötz Vol 1 p.65 it is also mentioned that Erlmeier, Brandt – the definitive work on early handgun ammunition – added to the confusion. For continuity purposes this round is listed separately on the website, but I support the White & Munhall view that this is the same as the 11.3mm Gasser M.1870. (Erlmeier, Brandt Ref. 170).