M9 Bayonet, based on the now-defunct Lan Cay.
The M9 Bayonet has been issued to both the American, and the Australian military for many years. It can be fitted to multiple standard issue rifles, and has seen service in many wars and deployments.
The M9 has been used notably in various videogames, such as its unusual variant featured in Counter Strike: Global Offensive, to being used before its legitimate period of use in Mafia III despite its invention not taking place until decades later.