Type 81 assault rifle

The Type 81 () is a Chinese-designed second-generation, selective-fire, gas-operated 7.62×39mm rifle (based on Kalashnikov and SKS actions) adopted by the Chinese People's Liberation Army (PLA) and has been in service since the mid-1980s.
It's a small arms family that consist of the Type 81, the Type 81-1 and the Type 81 LMG.
History.
The PLA's first attempt to replace their aging SKS and Type 56 assault rifle (a Chinese license produced AK-47) was the Type 63 assault rifle. This weapon, however, ended in failure due to a variety of issues resulting in a switch back to the weapons it intended to replace. The beginning of the Sino-Vietnamese border conflicts however, showed the PLA that their SKS and Type 56s were not as effective as they thought, causing their small arms development program to spring back to life.
The weapon was introduced into PLA service in 1981 but did not become widely distributed until the late 1980s. It replaced the SKS, the Type 56 assault rifle and even the RPD machine gun (LMG version), succeeding where the Type 63 failed. Its first combat use came during the latter part of the Sino-Vietnamese border conflicts of the mid-1980s. The PLA has replaced most of its Type-81s with the Type 95 or Type 03 series of weapons, though it is still in service in the reserves and armed police. 
An improved version is also used by the Bangladesh Army under the designation BD-08.
Design.
The Type 81 incorporates elements of the Dragunov, SKS, and AK series rifles. The design criteria it met included accuracy of 1.78 inch R50, that is 50% of the hits within a 1.78 inch diameter at 100 meters; improved controllability in full-automatic; the same reliability of the AK but a longer service life to approximately 20,000 rounds; and able to use existing AK and SKS production tooling at the time. Development was placed under Wang Zi Jun after the end of the Sino-Vietnamese border clashes in 1979.
The rifle retains the general layout of the Chinese Type 56 assault rifle, but it has a SKS-like short-stroke gas-piston design and other improvements to reduce recoil and muzzle jump, giving better firing accuracy. Notable physical differences from the Type 56 assault rifle include the stock of the rifle, the length of the action, bayonet, and the positioning of the front sight.
The most easily distinguishable feature of the Type 81 is the more exposed muzzle part of the barrel. The front sight has been moved back as a modification to be able to fire 22mm rifle grenades, which are slid over the unobstructed barrel muzzle now formed into a spigot-type rifle grenade launcher.
There is a significant gap between the trigger guard and the magazine on Type 81 rifles, while on the Type 56 rifle series the magazine is adjacent to the front of the trigger guard.
The non-detachable swing-out spike-shaped bayonet of the Type 56 rifle was also replaced on Type 81 rifles with the detachable Type 81 knife-bayonet.
Like its predecessors, the Type 81 is a series of weapons. The Type 81 (fixed stock) and Type 81-1 (folding stock) are 7.62×39mm caliber assault rifles with 30-round magazines, and the heavier Type 81 light machine gun (LMG) fitted with a 75-round drum magazine is used in the squad automatic weapon (SAW) role. Its sight remains at the front of the LMG barrel.
The Type 81 can be fitted with a Picatinny rail, bipod, foregrip, and flashlight. One such attempt to market picatinny rails for the Type 81 came from Bao Wa, a Hong Kong-based law enforcement supplier.