Why is my weapon twitching

ACTOR Rifle : DoomWeapon
  {
    Weapon.SlotNumber 4
    Weapon.SelectionOrder 1000
    Weapon.AmmoGive 30
    Weapon.AmmoUse 1
    Weapon.AmmoType "Clip"
    Obituary "%o was shot down by %k's assault rifle."
    Inventory.PickupMessage "You got the rifle!"
    Tag "Assault Rifle"
    AttackSound "brutaldoom/rifle"
    States
    {
     Ready:
        RIFG A 1 A_WeaponReady
     Deselect:
        RIFG A 1 A_Lower
     Select:
        RIFG A 1 A_Raise
     Fire:
        RIFG A 1
        RIFF A 0 A_GunFlash
        RIFF A 0 A_Quake(0.4, 3, 0, 400)
        RIFF A 1 A_FireBullets(5.6, 5.6, 1, 5)
        RIFF B 1
        RIFF C 2
        RIFF A 0 A_Refire
        Goto Ready
     Flash:
        RIFF A 1 A_Light1
        Goto LightDone
     Spawn:
        RIFL A -1
        Stop
    }
  }

I don't like how when I equip it ingame and it automatically fires a shot then twitches rapidly until I shoot. How do I fix my weapon?