Secondary gun is user choice same as pistol. however first wave x-45 is highly recommended to rate of fire
secondary skill is whatever ( i like shock turret to keep them from running but that's personal taste.)
HOWEVER, pistol needs to be a low level (210ish) so as to have both skills unlocked without the need for electronics. you use this to recover your super. shoot and reload shoot. the headshot hits will get your super back even faster.