In the post-World War 2 period (that is, the time period after 1945/1946), two infantry rifles rose to prominence in the East and West. For the former this became the classic Kalashnikov AK-47 assault rifle while, for the latter, this was the Colt M16 assault rifle based in the AR-15. Both were gas-operated weapon systems relying on a rotating bolt action and both chambered an intermediate rifle round, the AK-47 with its 7.62x39mm and the M16 with its 5.56x45mm cartridge. The 5.56x45mm was eventually standardized by NATO as the intermediate rifle cartridge-of-choice. For the nation of China, who has never been shy about local production of successful global products, both rifles were produced en masse - either under license or unlicensed. This proved the case with the ubiquitous M16 which became the "Type CQ" under Chinese manufacture. It was also known, more formally, as the "CQ 5.56".
The Type CQ retained the general form-and-function of its American predecessor in that it chambered the 5.56mm cartridge, fired from a gas-operated action, and fed from 20-/30-round STANAG detachable box magazines. The rifle retained the over-receiver carrying handle common the classic look of the Vietnam War-era M16, rear receiver charging handle, and ribbed handguard. There were slight changes to the shoulder stock's lines and the pistol grip's shape was reworked considerably.
It is believed that the Type CQ was only ever intended for interested export customers looking to perhaps acquire a suitable, Western-minded firearm no doubt at below-market cost. Two primary versions were ultimately marketed, one in semi-automatic-only (namely for the civilian marketplace) and the other offering the full-automatic support common to military firearms. A shortened assault carbine was also eventually developed to expand the line and this became the "CQ 5.56 Type A". The Type CQ was acquired in some number by Iran who went on to develop the local Model S-5.56 "Sayyad" as a straight-up Iranian copy of the Chinese model.
Despite it being disregarded as another Chinese knock-off of a successful product, the Type CQ went on to see relatively widespread adoption globally, counting users from Afghanistan and Cambodia to Thailand and Yemen, either for second-line security roles or full-fledged frontline army service. Several guerilla forces have also been keen on using the rifle - even today - where elements of the Free Syrian Army and ISIS forces have been known to use it. In any case, the CQ series appears to have been relatively successful alternative to the original M16.