Crossfire Probabilities: Percentage Success in each Die Roll Mechanism

My recent interest in Solo Crossfire got me thinking about the probabilities inherent in the Crossfire rules mechanisms. That means infantry direct fire / barrage / minefields, anti-tank direct fire, smoke, close combat, and rallying. Only read this post if you care about statistics of gaming mechanisms.


Infantry Direct Fire, Barrage, Minefields

Infantry Direct Fire, Indirect Barrage Fire and minefields all use a number of dice with a hit on 5+. The more hits the more the impact (1 hit = PIN; 2 hits = SUPPRESS; 3 hits = KILL).

Hit on 5+ Probabilities
Dice 0 Hits 1 Hit 2 Hits 3 Hits 4 Hits 5 Hits Mean Hits
1d6 67% 33% 0.33
2d6 44% 44% 11% 0.67
3d6 30% 44% 22% 4% 1.00
4d6 20% 40% 30% 10% 1% 1.33
5d6 13% 33% 33% 16% 4% 0.4% 1.67

When firing at a bunker the hits are on a 6 instead.

Hit on 6 Probabilities
Dice 0 Hits 1 Hit 2 Hits 3 Hits 4 Hits 5 Hits Mean Hits
1d6 83% 17% 0.17
2d6 69% 28% 3% 0.33
3d6 58% 35% 7% 0.5% 0.50
4d6 48% 39% 12% 2% 0.1% 0.67
5d6 40% 40% 16% 3% 0.3% 0.0% 0.83

Close Combat

Close combat is resolved by rolling 1d6 each and highest wins. There are a bunch of modifiers, but in practical terms the odds depend on the attacker modifiers. If the attacker can arrange a +5 modifier they have a 100% chance of victory.

Attacker Modifier Attacker Victory Defender Victory
0 50% 50%
1 68% 32%
2 81% 19%
3 91% 9%
4 97% 3%
5 100% 0%
6 100% 0%

Smoke

Off table mortars and artillery fire either barrage or smoke. Barrage is covered by the To Hit tables above. Smoke has a different mechanism. You throw 1d6 and on a 3+ the smoke lands. That is a simple percentage of 67% chance of success and 33% failure.


Rally

Rally rolls are 1d6. A PIN rallies on 4+ and SUPPRESS on 5+. Troop Quality gives a modifier: -1 Green; 0 Regular; +1 Veteran. Commanders also give a modifier but I’ll ignore this for the purposes of this chart.

Rally Probabilities
Status Troop Quality Failure Success
PIN Green 67% 33%
Regular 50% 50%
Veteran 33% 67%
SUPPRESS Green 83% 17%
Regular 67% 33%
Veteran 50% 50%

Same data presented with Troop Quality v Status:

Rally Probabilities
Troop Quality PIN SUPPRESS
Success Failure Success Failure
Green 33% 67% 17% 83%
Regular 50% 50% 33% 67%
Veteran 67% 33% 50% 50%

Anti-tank

Anti-tank direct fire uses two dice rolls. The first 1d6 is for Accuracy (ACC) and determines whether or not the attacker hit. The second 1d6 is a contest between the Penetration (PEN) of the shooter and the Armour (ARM) of the target; penetrating the armour destroys the target. 1 is always a failure; 6 is always a success.

The first table shows shows the individual percentages for ACC and for PEN. In the case of PEN there are values for each possible value of ARM. As it happens the percentages for ACC are identical to those for PEN versus ARM=4. Notice that at the extremes the percentages become static when they get to 0% or 100%. Note: This table ignores the rule that snake-eyes (double 1) is a failure and double 6 is a success.

Percentage for ACC and PEN
Rating ACC PEN versus
ARM=1 ARM=2 ARM=3 ARM=4 ARM=5 ARM=6
-3 0% 50% 33% 17% 0% 0% 0%
-2 17% 67% 50% 33% 17% 0% 0%
-1 33% 83% 67% 50% 33% 17% 0%
0 50% 100% 83% 67% 50% 33% 17%
+1 67% 100% 100% 83% 67% 50% 33%
+2 83% 100% 100% 100% 83% 67% 50%
+3 100% 100% 100% 100% 100% 83% 67%

The second set of tables show the chance to destroy the target, calculated as the percentage to hit multiplied by the percentage to penetrate. Because these tables factor in the combination of ACC and PEN they acknowledge the rule that snake-eyes (double 1) is a failure and double 6 is a success. I’ve shown the values for the ARM=1 to ARM=6.

Anti-tank Probabilities ARM=1
Accuracy Penetration
-3 -2 -1 0 +1 +2 +3
-3 3% 3% 3% 3% 3% 3% 3%
-2 8% 11% 14% 17% 17% 17% 17%
-1 17% 22% 28% 33% 33% 33% 33%
0 25% 33% 42% 50% 50% 50% 50%
+1 33% 44% 56% 67% 67% 67% 67%
+2 42% 56% 69% 83% 83% 83% 83%
+3 50% 67% 83% 97% 97% 97% 97%
Anti-tank Probabilities ARM=2
Accuracy Penetration
-3 -2 -1 0 +1 +2 +3
-3 3% 3% 3% 3% 3% 3% 3%
-2 6% 8% 11% 14% 17% 17% 17%
-1 11% 17% 22% 28% 33% 33% 33%
0 17% 25% 33% 42% 50% 50% 50%
+1 22% 33% 44% 56% 67% 67% 67%
+2 28% 42% 56% 69% 83% 83% 83%
+3 33% 50% 67% 83% 97% 97% 97%
Anti-tank Probabilities ARM=3
Accuracy Penetration
-3 -2 -1 0 +1 +2 +3
-3 3% 3% 3% 3% 3% 3% 3%
-2 3% 6% 8% 11% 14% 17% 17%
-1 6% 11% 17% 22% 28% 33% 33%
0 8% 17% 25% 33% 42% 50% 50%
+1 11% 22% 33% 44% 56% 67% 67%
+2 14% 28% 42% 56% 69% 83% 83%
+3 17% 33% 50% 67% 83% 97% 97%
Anti-tank Probabilities ARM=4
Accuracy Penetration
-3 -2 -1 0 +1 +2 +3
-3 3% 3% 3% 3% 3% 3% 3%
-2 3% 3% 6% 8% 11% 14% 17%
-1 3% 6% 11% 17% 22% 28% 33%
0 3% 8% 17% 25% 33% 42% 50%
+1 3% 11% 22% 33% 44% 56% 67%
+2 3% 14% 28% 42% 56% 69% 83%
+3 3% 17% 33% 50% 67% 83% 97%
Anti-tank Probabilities ARM=5
Accuracy Penetration
-3 -2 -1 0 +1 +2 +3
-3 3% 3% 3% 3% 3% 3% 3%
-2 3% 3% 3% 6% 8% 11% 14%
-1 3% 3% 6% 11% 17% 22% 28%
0 3% 3% 8% 17% 25% 33% 42%
+1 3% 3% 11% 22% 33% 44% 56%
+2 3% 3% 14% 28% 42% 56% 69%
+3 3% 3% 17% 33% 50% 67% 83%
Anti-tank Probabilities ARM=6
Accuracy Penetration
-3 -2 -1 0 +1 +2 +3
-3 3% 3% 3% 3% 3% 3% 3%
-2 3% 3% 3% 3% 6% 8% 11%
-1 3% 3% 3% 6% 11% 17% 22%
0 3% 3% 3% 8% 17% 25% 33%
+1 3% 3% 3% 11% 22% 33% 44%
+2 3% 3% 3% 14% 28% 42% 56%
+3 3% 3% 3% 17% 33% 50% 67%

Other resources

Nikolas Lloyd has a page on Crossfire probabilities as well. Although his interest is more about exploring alternatives e.g. 2.5d6, 3d6+1P, and 3d6+2P. See Lloydian Aspects: Crossfire Probabilities

3 comments to Crossfire Probabilities: Percentage Success in each Die Roll Mechanism

  • Thank you for posting this. It is very helpful.

  • Sampo Keskitalo

    Hello! Where do you get the Anti-Tank rule that 1 is failure and 6 is succes? All I could dig up was that double 1s are always a fail and double 6s always a success in anti-tank/vehicle fire. Your calculations effectively doubles 6-pounders success rate vs a Panther through the front armor.

    • Steven Thomas

      Sampo, you are quite right. Snake eyes are a failure. Double six a success. I relied on faulty memory. I’ll fix now.

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