In 2015, photographs and videos began circulating of several prototype rifle designs from the mid-2010s, chambered for an obscure experimental round, the 6x49, which was the Soviet Union's unified 6mm cartridge.The photos and videos show new developmental rifles chambered for the Soviet-era work resurfacing with some of the biggest Russian defense contractors.First publicly observed on 19 September 2015 during the Tsentr-2015 exercises in Donguz, Orenburg Oblast.