The Rate of Fire is how many Shooting dice the character rolls when firing the weapon. These additional shots must be taken at the same time, and each point of RoF grants the hero another Shooting die. A pistol with a RoF of 2, for example, gives a character two Shooting dice, which may be aimed at two different targets.

A submachine gun with a RoF of 3, for example, allows the player to roll up to three Shooting dice at once at up to three different targets. These shots can be split among all possible targets as the player desires, but must all be taken at the same time. A shooter with an Uzi can't fire one shot, then move and fire two more, for instance.

Wild Cards roll one Wild Die with the Shooting roll, and can use it in place of one of the Shooting dice if they choose.

Example: A special agent fires a submachine gun (RoF 3) at two terrorists. The agent is a Wild Card with a Shooting of d8, so he rolls 3d8 plus a Wild Die (d6). The player decides to put two shots into the closest terrorist and one at the further target. He rolls the two at the closest terrorist first, then rolls a third d8 for the second. He also rolls his Wild Die.

He scores a hit on each with his first two Shooting dice and misses with the third, but his Wild Die hit so he replaces one of the failed Shooting dice with it and gets his maximum three hits (since that was his RoF).

Savage Worlds Deluxe Edition p. 76