Mouriner-S13A is a continued development of the previous generations of Mouriner series main battle tanks, despite being one of the Mouriner-Seires MBT design the tank itself was very diffrent than its predecessor the S25B and S25V tank, it almost shares no simliarity than its predecessor other than round turret design and the hull itself, Mouriner S31A are build to replace older tanks such as S25B and S25V, also S24B

The S31A will be equipped with next-gen upgrades, one example is the Nerya-SAPS (Soft Active Protection system) placed on the turret, it works by blinding enemy SACLOS missiles, much like how the Russian shtora works, the S31A are also equipped with the new 133mm Autoloading gun system, according to some sources it can fire the SKK-045 DU Shell and SKK-055 HEATFS Shell, the autoloader system are reworked, by using a protected storage ammo load instead of classic Carousel type autoloader, making the tank safer

The S31A was first unveiled in the Euro-asia Arms expo in 2011, the design shown there was its export variant S31E with removed APS and slightly diffrent hull design, the S31A/E are expected to be mass produced in 2019 with numbers of 2000 units to replace aging marineon main battle tanks, but up until now there are only 1050 units sent and only 990 are ready for combat use, the delay of production was reportedly because economical problems

Controls
Pitch/Roll to control gun system
Yaw/Trim to control movement
AG1 will switch between RCWS and Secondary cannon (mounted on axis with the main gun) the default has the RCWS on and SC off
AG2 to activate APS, decoration only
AG7 to throw smoke launchers

Guns are all stabilized