Hammer of Math: The Cost of Overcharging in Warhammer 40k (Imperial Edition)

This week’s Hammer of Math takes a look at what price an Imperial player pays every time they fire an overcharged plasma weapon in Warhammer 40k. We’ll do a follow up at some point to cover the other factions.

In the 40k lore, plasma weapons are ancient creations of unparalleled value. Relics of the Dark Age of Technology, these devices are capable of unleashing incandescent destruction by firing pulses of highly charged plasma at a target that the Emperor/Chaos Gods/Boss wants dead. On impact they burn through armour and flesh with equal ease, but these power comes at a cost. Plasma weapons were designed with one simple idea; the weapon was more valuable than the being firing it. As a result they can overheat, and in lieu of becoming a bomb they instead vent the excess ionized gas into the surrounding area. That the surrounding area was previously occupied by a living creature is largely irrelevant, as the important thing is that the weapon remains intact to fire again.

In Warhammer 40k this overheating mechanism is represented by a mechanic based on the hit roll. Generally on a roll of 1 the target either takes a mortal wound or is killed outright, with no opportunity to save or mitigate the damage. The effective consequence is that every time a player fires an overcharged plasma weapon they are paying a price, that price being the product of the probability of overheat, the cost of the unit, and the amount of the unit degraded when the weapon overheats. For example a Hellblaster which costs 33 points firing an overcharged heavy plasma incinerator has a 1 in 6 chance of being completely destroyed, which means the cost per shot is 5.5 points.

The chart below shows all of the various plasma options for the Imperial factions. In addition to unit specific data (faction, name, type, wounds) the chart contains the weapons fired and the unit cost assuming just that weapon was purchased. The three columns on the right show the calculated results. The Probability / Average Losses column is either the probability of loss (if an overcharged result kills the target) or the average number of 1s rolled during an attack (if the overcharged result removes only some wounds). The Wounds Per Loss column is the wounds removed; often this value is equal to the Wounds characteristic of the firer because the model is destroyed. The Points Per Attack column on the far right is the final calculation; the average points lost for every attack made.

Takeaways

• Should you be the kind of player who thought dual Sunfury Plasma Annihilators was cool when you played Adeptus Titanicus, and decided to field an identical Warlord Titan at 40k scale, every attack will cost you around 10% of the value of the Warlord or the equivalent of a Knight Valiant.
• The plasma decimator on a Knight Castellan will cost an average of 50 points to fire in terms of self-inflicted wounds.
• The most costly choices are ones that should be obviously avoided, most notably putting a combi-plasma on an expensive Space Marine character like a Terminator Librarian. The chances of rolling at least 1 on a two dice is 31%.
• The most costly non-character unit is the Inceptor Squad where each model has a pair of plasma exterminators. On average the plasma exterminators will get four shots resulting in a 52% chance that the 60 point model will kill itself.
• Hellblasters with assault plasma incinerators are also in a pretty bad spot, with each model costing around 14 points thanks to the high probability of self-immolation.
• The Astra Militarum truly embody the notion that the gun is more valuable than the man firing it; a poor guardsman rapid firing a plasma gun only costs an average of 2 points.
• Re-rolling hits is essential for mitigating the effects of plasma. When a re-roll is incorporated you can divide the points per attack by 6.

Wrapping Up

While not a perfect analysis, particularly in the context of units with a lot of options like Space Marine characters, the numbers show that overcharging plasma weapons is often a surprisingly expensive choice. While some players are quick to make accusations of cowardice for not overcharging, the reality is that often it’s in your best interest to consider whether the benefits will outweigh the cost. This would be mitigated if overheating plasma weapons consistently inflicted a mortal wound on the bearer’s unit rather than destroyed the firing model depending on the gun and circumstances. This change would produce three effects:

1. It would eliminate the need to individually roll plasma hits to determine which model was destroyed, significantly speeding up play.
2. It would reduce the impact on character models.
3. In the case of a mixed unit would allow the wound to be transferred to another model, representing another warrior picking up the plasma gun from the charred remains of the previous bearer.

Hopefully the chart provides some useful insight into the models of your army. In a future article we’ll take a look a the Xenos and Chaos armies.

Thanks for reading! If you have any questions or comments feel free to drop us a note in the Comments below or email us at contact@goonhammer.com. That’s also the best way to suggest topics for future articles.