The AFF Universe Wiki also has an article on this topic: SAR Infantry Weapon

The Taldis SAR is a support weapon boasting a high rate of fire, great for keeping enemies pinned down.

It sits somewhere between the other heavy rifles and the LMGs: the low magazine capacity and reload time matches the other heavy rifles, but it has similar damage output and metal penetration to an LMG.

The SAR is also the only non-assault rifle to support all forms of modification.