The STK 50 MG, formerly known as the CIS 50MG,[a] is a gas-operated, air-cooled, belt-fed heavy machine gun developed and manufactured by Chartered Industries of Singapore (CIS, now ST Kinetics) in the late 1980s, in response to a request by the Singaporean Defence Ministry to replace the 12.7mm Browning M2HB machine guns then in ubiquitous service with the Singapore Armed Forces (SAF).

[1] The CIS engineers learned from the lesson of the canceled (lack of funding) American "Dover Devil GPHMG" program known as the Special Projects Group at Picatinny Arsenal led by Charles J. Rhoades.

Curt Johnson and Phil Baker developed the original concept to create a modular weapon suited for modern tactical doctrines and production techniques.

The CIS 50MG utilises the same "constant recoil" system used in the Ultimax 100 and it also has a quick-detachable barrel equipped with a carrying handle to facilitate the ease of barrel changing under combat situations or during operational manoeuvres.

[2] The one unique feature of the weapon is its dual belt-feed system, the system allows for fast and easy switching of ammunition from standard ball rounds to the Raufoss Mk 211 Armor-Piercing-Incendiary rounds or the Saboted light armor penetrator (SLAP), which are capable of penetrating a rolled homogeneous armour plate with a thickness of 25 mm (0.98 in) from a range of 1 km (0.62 mi).