The Chinese Army has only recently begun receiving these weapons. These large caliber sniper rifles first appeared from Chinese manufacturers in 1999, when the M99 showed up. A few years later the M06 (as an M99 with a few minor changes) appeared. A decade later another version, the QUB09, came along. All three of these are bullpup (magazine behind the trigger) designs and are built by a state owned weapons factory.
There are many other 12.7mm rifles available from Chinese suppliers. For example, the AMR-2 is a more conversional design (magazine in front of the trigger). The M99/M06/QUB09 all weigh about 12 kg (26.4 kg), while the AMR-2 is a little lighter at 11 kg (24.2 pounds). The M99 series can use 12.7x108mm or 12.7x99mm rounds, while the AMR-2 only handles the 12.7x108mm cartridge.
The Chinese consider all of these models to be anti-vehicle/material rifles. Sniping against people is a secondary mission, and the Chinese rifles are not as accurate at longer ranges (over 1,000 meters) as similar Western models. Most of these rifles are sold to foreign customers (military, police, private individuals, and any one with enough cash and a good excuse).
It's only recently that China has begun delivering large numbers of 12.7mm rifles to its own troops. The problem is that there are a lot of options in this area. And in the last decade there has been a lot of development action in large caliber sniper rifles. This may be one reason why the Chinese Army has not invested heavily in this weapon.
For example, when the Barrett company introduced the first .50 caliber (12.7mm) sniper rifle in the 1980s, it was not the only company working on the concept. The Steyr-Mannlicher company, of Austria, was also developing a large caliber "anti-material" sniper rifle. While Barrett quickly took most of the market, Steyr continued to work on their weapon. Along the way they upped the caliber to 15.2mm and focused on discarding sabot ammo fired from a smoothbore barrel. The discarding sabot technique was first used with anti-tank guns. Most modern 120mm tank guns fire a shell that uses a smaller 25mm "penetrator". The 25mm rod of tungsten (or depleted uranium) is surrounded by a "sabot" that falls away once the shell clears the barrel. This gives the penetrator higher velocity and penetrating power. Each round weighs 139 grams (5.25 ounces) and is 20.4 cm (eight inches) long. The Steyr 15.2mm delivers a 20 gram (.7 ounce) tungsten "dart" that moves at 1,516 meters (4,700 feet) per second and can go through 40mm (1.6 inches) of armor at 1,000 meters. This weapon is called the IWS (Infantry Weapon System) 2000 and has a 122cm (48 inch) smoothbore barrel and weighs 18.2 kg (40 pounds). It uses a five round box magazine. The weapon breaks down into two loads, so a two man sniper team can easily carry it. It's a bullpup design that is 168cm (5.6 feet) in length overall.
Steyr found that there was not much of a market for the weapon. The 12.7mm sniper rifles have about the same sniping performance as the IWS 2000, and Barrett introduced a 25mm rifle back in 2004. However, the dependence on discarding sabot ammo only may prove interesting. Discarding sabot rounds has been around in infantry weapons for some years. They are available for 7.62mm and 12.7mm weapons and are interchangeable with standard ammo. The 7.62mm discarding sabot has a 5.56mm penetrator, and the 12.7mm round uses a 7.62mm penetrator. However, using a discarding sabot in a rifled weapon does not give you as much speed as a smoothbore. But that's not much of an edge. Then again, it may be enough for the Steyr 15.2mm rifle to eventually catch on.
Thus, if you want a material destruction rifle, special ammo is an area of promise. But China is not yet doing anything here. It has also been found that smaller bullets (like the popular 8.6mm) give about the same range as the 12.7mm for sniping, while using a smaller and lighter rifle. Thus it appears that the Chinese are waiting for development activity to settle down before investing a lot of money in this type of weapon.
Meanwhile, export customers, like the UWSA, are eager to take the M99 and use it to block army traffic on the few roads that snake through the hills and forests of northern Burma.