So a lot of my friends have asked me how to use the m303, so im guessing not that many people know how to use the special abilities for it.
So if you click R with a fully loaded m303, it will change the mode for firing the m303 The first mode you start with on the m303 is the laser guidence mode, it fires wherever the laser is pointing. The second mode for the m303 is called position marked mode, if you right click with this mode you can set a destination for where you want the m303 to fire at. This is not reliable in small areas, becuase it takes a while to turn, so use this in a larger area if you want it to hit a certain spot. The third mode for the m303 is called manual, this is exactly like the laser guidence mode, except it does not use a laser to show where it is shooting. The fourth and last mode is called Heat-Seeking, This mode is like the position marked mode but it finds the closest player and tries to lock onto that person, this does not lock onto gang members or npc's, but will lock onto anyone elce. This is also not reliable in small areas because it does take a while to turn like the position marked mode
I hope this helped anyone that did not know these features of the M303.