The United Wa State Army has acquired a number of M99 12.7mm Anti-Material Rifles from China, reports China Defense Blog. These semi-automatic rifles are either chambered in 12.7x108mm Russian or in .50 BMG.
The United Wa State Army is a an armed rebel group in Burma (Myanmar) that had a long standing cease-fire with the ruling military Junta until 2009 when the Myanmar Armed Forces clashed with them and other “ethnic armies”. China was furious with the Burmese government for the instability it caused.
The United Wa State Army pays it soldiers a salary of $7.50 per month. These rifles, which must surely be worth at least $2,000 each, represent a significant investment. They were likely traded with China in exchange for land. Chinese has extensive farming and quarrying operations in Burma.
Many thanks to Albi for the tip.