TEXT: How to Shoot your P90
  Each P90 holds 50 bullets. You have 3 ways to fire it:
  Single Shot
  If you only fire one shot, you roll your Shooting die normally. Damage is normal.
  Full Auto against one or more targets
  You can fire up to 3 attacks per round. You can roll a separate Shooting die for each bullet at -2 each.
  You only get one Wild die. Each attack that hits will do normal damage. Firing all 3 will expend 10 
  bullets.
  Three-Round Burst
  You can fire all three shots as a three-round burst at one target. You will make one Shooting roll at 
  +1. The damage roll will be at +1 as well. You will expend 3 bullets.
  Damage
  Damage will be 2d8 per successful hit. Each attack will ignore 2 points of target's toughness.
  
SOURCE: textdata/thevault/Savage Worlds/Fan/Stargate/Savage Worlds - Stargate - P90 Shooting.pdf