7.7x58SR Type 92

This round was adopted by Japanese army in 1932 (2592 per Japanese calendar then in use) as a dedicated medium machine gun round, to improve machine guns performance compared to earlier weapons, chambered for relatively ‘weak’ 6.5x50SR ammunition. Only machine guns were manufactured for this round, and no weapons for it were made after the end of WW2. Today it is strictly obsolete.