The Zijiang M99, officially designated the QBU-99, is a Chinese anti-materiel rifle.
Little is known about the history of the M06, though it has seen Chinese service since 2005. It has been used by the People's Liberation Army Marine Corps, though it has also been seen being used by Syrian Free Army rebels during the Syrian War, and it is thought that Syrians acquired these weapons via brokerage through Qatar or Sudan.
This gas-operated semi-automatic anti-materiel rifle uses direct impingement as an action. Its design appears to be based on the Accuracy International AS 50. A large muzzle brake is fitted on the end of the barrel to counter the massive recoil produced by the cartridge. With the appropriate ammunition, the M99 is capable of 1.6 MOA accuracy, as seen in Pakistani military trials. The M99 comes with both a bipod and an adjustable monopod at the rear of the weapon, mounted on the stock.
Variant chambered for .50 BMG. It is assumed that this is an export variant.
Bullpup variant fed from a drum magazine. Due to the position of the magazine, the scope is mounted off to the side via a Picatinny rail.