As I've noticed with the forums talking about Snap Shot, many different opinions have been made for what snap shot does and restricts.
Here's my breakdown:
So, after an enemy moves within range 1 and in your primary firing arc, a ship with Snap Shot may perform an attack using 2 attack dice.
Note: you can only attack at range 1 and with only 2 attack dice because the red number indicates how many dice you roll (similar to missiles and torpedoes), and the white number indicates what range the target of the attack must be in (also like missiles and torpedoes).
The attacker cannot modify (for example, spend a target lock,) their attack dice. Since this EPT is a secondary weapon, the range bonus is not applied to the attack.
The defender rolls their defense dice, and may modify their dice (for example, they may use an ability or upgrade).
Note: if the defender has the option to roll more defense dice (such as with Stealth Device,) they may roll the appropriate amount of defense dice.
After the attack is resolved, the ship that just performed its maneuver before the attack may perform actions, and continue as normal.
Note: the card states "you may not attack during this phase". By this, the card simply states that you cannot use any ability that allows you to attack, or attack again (from gunner or Luke Skywalker) during the activation phase. After the activation phase, you may attack whenever it is appropriate for you to do so.
Snap shot is not discardable.
This is just my understanding of it, and I wrote this up for the players who are confused of the what the card exactly does.
If I missed anything, or if I stated anything wrong, please let me know.