TEXT: Combat Crib Sheet for T4:
  In all cases to find the [Difficulty] from the Range Effects Table below.
  1) Snapfire.
  Allows character to move and shoot without any weapon type DMs. Uses 1 round.
  2) Burst fire. MAY BE AIMED IF PLAYER IS STATIONARY. 
  Only affects designated primary target. Negative DM (Range number /2) rounded 
  up. Damage to target is doubled after armour effects. Uses 5 rounds.
  3) Autofire.
  CANNOT BE AIMED.
  Designate primary target. Range number is a negative DM against primary target. 
  Damage to primary target is doubled after armour effects.
  Adjacent targets also attacked. To hit DM is 2x Range number. Normal damage 
  on hit. Uses 5 rounds per target. If insufficient ammo GM decides who gets hit from 
  adjacent targets.
  4) Aimed fire. 
  CANNOT BE USED IF MOVING OR HIT IN COMBAT.
  Reference weapon range on table. The range number is the positive DM.
  5) Suppressive fire.
  Combines held action with autofire. Any target entering or the designating players 
  next turn is attacked as an autofire adjacent target, and 5 rounds are used up.
  Max Range is 2 bands past weapon range stat. -1D per band past ‘Long’.
  Misc Notes:
  (a) Plasma weapons do 1/2 of their explosive damage along line of fire. Also require successful  task 
  roll of (Endurance) < Average (2D) or be blinded for 1D hours if no protective equipment.
  (b) Called shot - raise difficulty 1 level and either increase or decrease damage, or hit specific point.
  (c) Held action -hold until end of next round - takes precedence over another character’s action.
  (d) Explosives are either Fragmentation or Concussive and ignore maximum damage limits. Assume 
  concussive if not explict. Fragmentation is effected by armour, Concussive ignores armour or cover 
  unless pressure sealed. Damage done halves every 1.5m from the impact ‘2m Square’. They attack all 
  targets in the area of the blast. Optionally, may consider only 1/2 
  (e) Reloading takes 1 action for a magazine based weapon, 2 for non-magazine weapons.
  (f) If firing into HTH combat, apply a -3DM. If miss occurs roll to hit again against adjacent target.
  (g) Thrown weapons difficulty  is two range numbers higher than normal, max range Short.
  (h) Darkness -6DM to Short, -9DM >Short, Poor Visibility -3DM, may use special aids to avoid.
  (i) Cover -  conceals and protects (GM may give armour rating). Partial cover gives -4DM to hit, 
  Concealment -1DM.
  (j) Size - Football -3DM, Car +3DM.
  (k) Indirect fire task (Dex + lowest of Fwd Obs or  Weapon) < Difficult (2.5D)
  (l) HTH task (Dex + appropriate skill) < Average (2D)  DMs: Improvised weapon -1 or -2,  -opponents 
  weapon skill. See pg 55 for fencing, grappling etc, unarmed does 1D damage.
  Range Name Distance (m) DM (aimed)
  DM (Burst) DM (auto prim/adj) Attack Rating Dice Code
  Contact
  0-3m
  0
  0
  0/0
  Easy
  1.5D
  Very Short
  4-15m
  1
  -1
  -1/-2
  Average
  2D
  Short
  16-45m
  2
  -1
  -2/-4
  Difficult
  2.5D
  Medium
  46-150m
  3
  -2
  -3/-6
  Formidable
  3D
  Long
  151-450m
  4
  -2
  -4/-8
  Staggering
  4D
  Very Long
  451-1500m
  5
  -3
  -5/-10
  Impossible
  5D
  
SOURCE: textdata/thevault/Traveller/GURPS Traveller/GURPS Traveller Combat Cribsheet.pdf