Hammer of Math: Weapon Changes in 40k 10th Edition

This week’s Hammer of Math looks at how 10th Edition will change expectations regarding some of the most common weapons in Warhammer 40k.

Warhammer 40k is heavily driven by its lore, and a big part of that lore is the differentiation of the mainstay weapons. Lasguns are weak, plasma guns melt things when they aren’t killing the firer, multi-meltas are the premiere anti-tank option, and lascannons are precision weapons of radiant tank killing death. That lore understandably drives game mechanics, which means that from Necromunda to Kill Team getting hit by a multi-melta is going to leave a pair of smoking boots.

Black Templars Repulsor Executioner. Credit: SRM

With the 10th Edition of Warhammer 40k Games Workshop has chosen to vastly expand the range of Toughness and Strength characteristics to add more granularity to the game. Where in the past a S8 weapon hitting a T8 vehicle was generally the golden standard, in 10th Edition S8 weapons are focused on elite targets, while you need S12 or higher to take on the most heavily armored vehicle.

The New Toughness Regime

Based on the latest Tyranid and Space Marine releases, it seems like the following gaps are reasonable representation of the Toughness and armor spreads.

  • Light infantry targets are still T3/5+ while Marine Equivalent hasn’t changed at T4/3+.
  • The realm of what’s considered a heavy infantry target ranges above light targets. Terminators are T5/2+/4++, Gravis is now T6/3+, while Tyrant Guard are T8/3+. This group was usually T5/T6 before.
  • Light vehicles like Dreadnoughts are now T9/2+ or T10/2+. Rhino chassis vehicles and Gladiators are T10/3+ or T11/2+ in the case of the Vindicator. The Tyranid equivalents are as high as T11/3+ like the Haruspex. Generally this target was T7 in 9th Edition.
  • Heavy vehicles are in the realm of T12/2+ like the Land Raider or Tyrannofex. The Repulsor is also T12 but with a 3+ armor save. Previously these targets were generally T8.

We’ll go with T4/3+ as the light infantry target, T6/3+ as the heavy infantry target, T10/3+ as the light vehicle target, and T12/2+ as the heavy vehicle target. Expanding the range of Toughness characteristics from T3 through T8 to T3 through T12 gives the designers a lot more room to work with, and enables some nuance in weapon effects.

Changes in Weapon Profiles

We’ll be using weapon profiles from the Space Marine index and assume that they will be largely consistent across the other books. We’re assuming the weapons are firing from a vehicle platform or a stationary infantry unit and are therefore hitting on a 3+.

Land Raider. Credit: Rockfish
Land Raider. Credit: Rockfish


The lascannon has always been intended as the long-range strike weapon, and it remains intended for that role. The profile went from S9 to S12, but kept the same AP of -3 and adds one point of damage (going from D6 to D6+1). Twin-linked variants are now less effective; where the 9th Edition version received two shots the new version has the [TWIN-LINKED] rule.

The Heavy Infantry target is likely the most difficult to calculate since it’s so diverse, but it’s notable that the weapon dedicated to killing heavy targets suffers from the top Toughness characteristic now equaling the weapon profile. To have a better than even chance of wounding the target will require weapons like the Heavy Laser Destroyer.

Credit: Kasra Houshidar

Plasma Weaponry

Plasma weaponry has been largely unchanged. The profile starts at S7, AP -2, and 1 point of damage. Supercharging adds a point of strength, AP, and damage but leaves the profile otherwise unchanged. The macro version for Space Marines starts at the overcharged profile for a plasma gun and then adds more when the weapon is overcharged.

The changes to plasma are stark, with a significant reduction in efficacy against vehicle targets while the effect on lighter targets is largely unchanged. While the weapon has a high AP which makes it useful against armored threats, taking on the high Toughness characteristics of heavier threats will require re-rolls or [LETHAL HITS] with some kind of bonus for getting extra Critical Hits.

Rainbow Warrior Eradicators by Craig “MasterSlowPoke” Sniffen

Melta Weaponry

In 9th Edition, the melta profile was S8, AP -4, and dealt D6 damage with a +2 bonus at half range. In spite of heavy threats getting significantly higher, the 10th Edition melta profile only received one extra point of strength. In the lore, melta weapons go through armor like it was paper and deal insane amounts of damage. In 10th that seems less likely.

As with plasma, melta sees a significant reduction in the probability of wounding against heavier targets. Given that the number of shots hasn’t changed and the weapon still has a remarkably short range, it’s difficult to see how this weapon is a viable choice when compared to lascannons.

Grav Weaponry

Where lascannons got a major strength boost and the other weapons generally didn’t see much of a change, grav weaponry gained the [ANTI-VEHICLE 2+] effect to practically guarantee a wound against VEHICLE targets. In 9th Edition the grav cannon had a profile of S5, AP -3, and one point of damage unless the target had a save of 3+ or better. In 10th the profile is S6, AP -1, and D3.

This one is weird. The change in strength makes the weapon less effective against INFANTRY targets, while the weapon gets a boost against VEHICLE even though the AP is reduced from -3 to -1. If the target is a MONSTER instead of a VEHICLE then the light targets take a 7% drop in probability while the heavy ones face a 11% drop.

Wrapping Up

The major thing to take away from here is that expectations regarding how weapons perform in 10th should change significantly. While the range of Toughness characteristics has expanded significantly, the Strength characteristics of plasma and melta weaponry has not. Even lascannons are less effective against heavy targets like Land Raiders. I wouldn’t be surprised if armies like Imperial Knights or monster-heavy Tyranid forces pose a significant challenge to simply wound.

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