Evolution of 40k: Plasma Cannons


40k has changed significantly since the days when I started collecting at the very tail end of Rogue Trader.  I thought it would be interesting to dissect features of the game and see how they’ve evolved over the past 24 years.  While it would be great to compare entire editions across the ages, this recurring segment will look at various parts of the game to see how they’ve changed, and how they seem to have changed the game themselves.  

For our first installment of Evolutions of 40k, we’re going to look at Plasma Cannons.  Granted, there are differences in the way the game was played in those times.  The idea of a “short” and “long” range for a given weapon has been replaced, as have weapons that do multiple wounds worth of damage (for the most part).  So it’s hard to give an apples to apples comparison, but let’s just look at it for what it’s worth.  

Rogue Trader

In Rogue Trader (aka. “first edition), plasma cannons were classified as “very heavy weapons;” lumped into the same category as defense lasers!   They were classified as “suitable only for use on large vehicles or as emplaced defenses.” (RT Rulebook pg 87).    

Statline from Rogue Trader Rulebook (copyright Games Workshop 1987)

But that’s a matter of terminology because, in 1987, “plasma cannon” was a compeltely different weapon.  The true equivalent was simply called a “heavy plasma gun.  The stats from the Rogue Trader Rulebook (pg 84) for this gun were as follows:  

  • Strength: 7 / 10
  • Range: 0-20″ (S), 20-40(72)” (L)
  • Save Modifier (AP): -2 / -6
  • Blast: 1″ (radius)
  • Damage: d4 / d10

The first thing you’ll notice is that the weapon had two completely different profiles.  These represented firing plasma had at either of two options: sustained fire and maximum power.  Before you fired, you had to declare which statline you were using (more on this later).   

So, from an apples to apples comparison, the two stats that have stayed equivalent throughout the various editions are Strength and Blast (radius).  As you can see, the strength of the blast was either 7 or 10, depending upon the power of the shot, so it did a bit better job at destroying infantry.  Against vehicles, it was also effective, because vehicles in this era also had toughness and armor saves (as Armor Values hadn’t been invented yet).   

To balance it out, the blast was a little bit smaller, since the blast characteristic was measured in inches of radius, giving it the equivalent of a 2″ modern day template.  Shooting with template weapons was handled a little differently though.  First, you’d place the template where desired, and then roll for scatter, once you it was determined where the final shot landed, you’d roll to hit for each model beneath the template (including partials), and then wound accordingly.  Because of the relatively small blast marker, heavy plasma guns were prone to scattering only 1/3rd of the time., making it somewhat accurate.  

Chaos renegade of Khorne with heavy plasma gun. Painted by Bsmoov of A Gentleman's Ones.

Now, on to the two characteristics that are drastically different than the way we play today.  First, let’s address range. Back then, weapons all had two range numbers: one to indicate when you were in short (S) range, and another for long (L).  You could fire at either range, but you received penalties to hit when firing at targets that were farther away.  With the standard shot, it could reach 40″, but it was possible to fire twice as far as it’s current-day counterpart (albeit at somewhat reduced accuracy)–if firing at maximum power  

The downside of using high power was that, once you shot it, it took 3 turns of inactivity for the gun to recharge!  Of course, there weren’t random game length rules to reduce the game to 7 turns, but still, that was a significant amount of downtime.  

The other stat is a larger stretch from the existing rules, and that’s the Save Modifier.  In third edition, they did away with the concept of save modifiers, and replaced them with a stat called AP.  Save modifiers were a basic enough concept, you reduced the effectiveness of any armor save by the amount indicated (in this case, -2 or-6).  So, if fired at high power, a space marine who would normally have to roll a 3+ (on 1d6) would now have to roll a 9+ (good luck!).  However, against the standard shot from this weapon, a marine would still receive a 5+ armor save.  

The other notable differences were in the special rules:  

  1. Carrying a heavy weapon was hard to do, so just by holding this weapon, you were force to move 2″ slower than you normally would.
  2. Like with all heavy weapons, you had diminished assault abilities just by carrying this.
  3. This particular weapon could not move and fire (no change from existing rules).
  4. Following Fire – the biggest difference, in that you were able to continue to fire upon each successful wound you scored.  So, an accurate gunner could score an innumerable amount of hits with this in “sustained fire” mode.

Plasma in general, also came in the form of guns, pistols, and grenades (all of which stuck around until 5th edition, at which point plasma grenades simply became known as “assault grenades”), but that’s for another post…  

Summary: Rogue Trader era heavy plasma fired at longer range, were stronger, and drastically more complex than they are nowadays.  They were also less prone to bypass armor, and had a smaller template.   

2nd Edition

In 2nd edition, the gun itself remained relatively unchanged.  In fact, they’re identical across the board, except for the blast radius:  

  • Strength: 7 / 10
  • Range: 0-20″ (S), 20-40(72)” (L)
  • Save Modifier (AP): -2 / -6
  • Blast: 1.5″ (radius)
  • Damage: d4 / d10
Templates got a little larger in the new edition (in fact, I’m not sure they officially existed until 2nd edition.  Any truly old-school gamers remember?) 


Devastator with heavy plasma gun from Codex:Ultramarines (copyright Games Workshop)

2nd edition also lays claim to the weirdest rule change when it comes to heavy plasma guns (and no, obviously it’s not the name change to plasma cannons, as that didn’t happen until third).  No, the award for weirdest rule change was the “simplification” of the two different types of power for the gun.  

If you recall, in Rogue Trader the powers were “sustained fire,” and “maximum” power.  In the great rules change of ’93, the powers that be saw fit to change these titles to “low” and “high” power.   

The stats of the weapon did change though, so I can’t berate them too much.  Previously, the “following fire” rule allowed you to keep firing after each successful hit, whereas this mechanic was replaced 



with the classic, red “sustained fire dice” in 2nd ed (complete with “jamming” mechanic).  Of course, this is all a moot point because plasma lost this ability with the new edition.  Likewise, the new high powered option also had a slight tweak in the rules.  Instead of having to wait three turns in between shots, you could now fire it every other turn (which lead to models firing at high power, then moving the next turn–in a sense, avoiding the penalty altogether).  

The shooting rules vs. vehicles also changed in this edition, which led for plasma to be slightly less effective against vehicles.  Vehicles now had armor values, and the general rule for how effective a weapon could penetrate that armor would be the strength of the weapon, plus the damage, plus a d6.   The result is a score between 9 and 17 (with an average score of 13.  With this change, at anything but high power, plasma became an anti-infantry weapon.  

Summary:  The 2nd edition variety weapon lost the following fire rule, but had a slightly larger blast, and less down time between strength 10 shots.  Due to overall changes in the way vehicles work, all plasma weapons tended towards anti-infantry weapons instead of general all-purpose of old.   

3rd Edition:

At this point, plasma receives a significant facelift, as does the entire flow of the game.  The stats as we now know them (AP, lack of a “damage” stat, etc.) are instituted:  

  • Strength: 7
  • Range: 36″
  • AP: 2
  • Blast: 3″ diameter

This newly modified statline as it was created in 1998 is the same as it appears today, though the weapon was not identical.  

So, let’s go over the easy parts of the statline.  First, you’ll notice that the premise of high and low power have been eliminated.  This was the edition where GW was accused of “dumbing down” 40k, and complex rules like this had died in droves.  Largely though, the weapon adhered to the statline of the low-powered heavy plasma of old.  Strength and blast stayed the same (though blast was now measured in diameter), and range is roughly equivalent, but like most everything else in the game, is factored on a distance in feet. 

This is also the edition where it officially becomes named as a Plasma Cannon.   

Aside from that, the only other statline change is that without the existance of the “save modifier” mechanic, plasma weapons in general have been increased to AP2.  Whereas, terminators still received saves against plasma (even at maximum power) in previous editions, they wouldn’t any longer.  Largely because of the changes to the way AP was handled, plasma weapons began to dominate the battlefield in 3rd edition.   

Another change to this weapon came in the form of how template weapons were handled in the new edition.  Whereas you previously placed a template, and then rolled to hit each model underneath, in 3rd, models you placed the template and rolled to hit just once.  If you hit, it landed right there, but a miss would have it deviate.  Once you finished deviating, models wholey covered by the template were hit automatically, and those that were partial were hit on a roll of a 4+.    These changes made it easier to hit the original target, or large groups of models clustered in a small area–none of which would now get an armor save.   

Another subtle change in the new Plasma Cannon was that the Eldar no longer had access to them.  Instead, they were given a “star cannon,” which was quite similar, but instead of a blast radius, it had multiple shots.  In those days, this , but a plasma cannon by any other name…  This was–without a doubt–the best heavy weapon an Eldar army could field at the time.   For the marines, who could still use this weapon, the sculpts of this edition also changed from the classic shoulder-mounted heavy weapons to an underslung, hand-carried weapon.  

Lastly, this is the edition when the concept of overheating was created via the “Gets Hot!” rule.  On a roll of a 1 to hit, the weapon over-heated and caused a wound to the firing unit.  It wasn’t terribly horrible though, as the wound allocation rules allowed the plasma bearer to stay alive at the expense of one of his less valuable squad-members.  

Summary: 3rd edition caused an explosion in plasma (quite literally when you figured in the “Gets Hot!” rule).  The changes to armor penetration of the new edition and granting this as the only blast weapon with AP2 made it one of the most popular weapons in the game.  Despite the overheating rules, the weapon was clearly a front-runner in any competitive list.   

4th edition

Strangely, the stats of the gun in this edition look eriely similar to those of 3rd:  

  • Strength: 7
  • Range: 36″
  • AP: 2
  • Blast: 3″ diameter

Though the stats of the weapon didn’t change between 3rd and 4th edition, the days of plasma proliferation had come and gone.  This was due to the changes in the way blast weapons were handled with the release of 4th edition.  Previously, you could place the template anywhere you wanted, and roll to hit based upon that location, though in 4th edition you were then required to center the blast on a model.   

Gone were the days that you could place the blast in the center of a squad to maximum the number of casualties, were then forced to center the template on a model.  The rules for blast templates no longer required you to center it on a model, instead they stated that  it should be placed so that one model was under the hole of the template.  This subtle difference allowed you to position a template towards the edge of a base, enabling you to potentially catch more in the blast–especially true for models with larger bases.  Since it’s a 3″ template, and unit coherency was at 2″ between models, it was a rarity for you to be able to hit more than a single model with the blast (unless it deviated).  Furthermore, that the new shooting rules stated that you rolled to hit the unit, and on a miss, there was no deviation: the shot landed harmlessly elsewhere, causing less collatoral damage overall.  The net effect here was that significantly less casualties were caught in blasts.  

Across the board, points cost for plasma weapons also increased, and the effectiveness of them against key targets (like terminators) was conversely decreased, as terminators also earned their 5++ invulnerable save due to the proliferation of AP2 weaponry.   Another reason for their decline was they were more restrictive in who was allowed to carry it in this edition.  Previously, tactical marines could use this weapon, but in 4th edition, it was pushed out of the troops slot and into the arms of devastators & veterans.   

The last nerf to plasma was the change of the “Gets Hot!” rule when it applied to multiple shots.  It now would overheat on a 1 or a 2 if you’re firing two shots, and a 1, a 2, or a 3 if you were firing three shots in a turn (though I can’t think of a single plasma weapon that could fire three shots).  So, what’s this have to do with Plasma Cannons, since they’re a heavy 1?  

Well, nothing.  I was just pointing out the nerfing of plasma as a whole.  


Ultramarine with plasma cannon.

Summary:  Despite no change in stats, plasma cannons completely died out in this edition due to rules changes.  GW recognized the fact that plasma was overpowered in third edition, and overcorrected in fourth edition.  Instead of bringing them inline as a balanced option, they nerfed them into oblivion.  Perhaps that’s an overstatement: it wasn’t a horrible option, it just paled in comparison to the other guns available.  Few people bothered with this option in fourth.   

5th edition

Surprise, surprise:  

  • Strength: 7
  • Range: 36″
  • AP: 2
  • Blast: 3″ diameter

Again, no change to the statline, but as we’ve seen in previous editions, changes to the surrounding rules do have an effect on the weapon’s performance.  

Firstly, the weapon was again allowed in more units.  Tactical squads were able to carry them again (though marine varient ‘dexes since: either don’t allow them, or don’t make a feasible option.  So, the net effect is kind of a wash.  

The big changes in 5th edition though have to do with the changes to what constitutes a cover save, and the changes to the vehicle damage chart, both of which have a significant impact on Plasma Cannons.   Since this is primarily an anti-infantry weapon, the changes to vehicles aren’t a huge nerf to the gun, but they are worth noting.  With strength 7, the chances of actually destroying an AV12 vehicle in one shot are miniscule (in the realm of 4-6% per shot), which gives way to the rise of mechanized forces that are so prominent in today’s net lists. 

As for the changes to cover, having an AP value of 2, most units won’t receive any sort of save against plasma cannons, aside from cover.  The new rules allow a model a cover save if any part of it is obscured–so an inability to see the toe of a model would grant it a save.  Furthermore, in order to expedite the game, cover was almost universally improved to a 4+ save, whereas previous editions had many forms of 5+ saves.  These changes necessarily have an impact on all weapons with a low AP value.  

On the plus side, deviation rules changed to reduce the distance of a weapon’s scatter by the firing model’s ballistic skill, drastically increasing the chances to hit nearby models, or even your original target on a miss.  

 As a whole, I rarely see plasma weapons (of any type) fielded in games anymore (though there is apparently a viable “competitive list” based around heavy plasma and Lash of Submission).  Despite the fact that cover saves are rampant in games today, I attribute the further decline of plasma solely to the rise of mech.  Melta does a better job in almost all ways (excepting range) to a comparable plasma weapon, and has no drawback of overheating.  Granted, it doesn’t get a blast template–nor can it doubletap at short range, but these are often overlooked, since the key focus is destroying vehicles.   

The curious part about this is that netlists everyone praise the value of str6 weaponry in it’s ability to kill light tanks, but seemingly nobody has any love left for plasma.  Granted, str6 weapons (multi/scatter-lasers, psycannons, etc.)  tend to have a slightly higher rate of fire, but they’re also all heavy weapons of the move or fire variety.  I guess that matters little when they’re mounted on a vehicle though… 

Summary: Without changing the stats of plasma, it somehow managed to get even less popular in 5th edition.  Cover saves and vehicles proved to be more than a match for this weapon of old…  The one positive change here is the changes to deviation rules. 

6th Edition

Now is the time for pure speculation (Oh Goody!).  What do you think will happen in 6th edition in regards to Plasma Cannons (or for plasma in general?).  

Marine from Dawn of War (Copyright Games Workshop & Relic Entertainment)

As for the stats of the weapon itself, I doubt we’ll see much change there at all.  What I’d love to see is a slight decrease in points across the board for plasma weapons and have them changed to AP3 weaponry.  With this change, you could even go so far as to remove the “Gets Hot!” rule altogether (though I think it would be better to reduce it to only occur on a roll of a 1–no matter how many times the weapon fires).  This would give the marines a viable AP3 option (I can’t think of any they have), while the reduction in points and increase in survivability for the weapon holder would increase the liklihood that someone would actually use it again. 

Another neat option would be to give it a special rule, akin to pinning.  Perhaps models shot at by plasma could be blinded (-1 BS/WS for the next round), or could continue to burn for rounds to come?  While that sort of rule is fun to think about: it’s too “2nd edition” to see play.  The continuous streamlining and simplification of 40k will ensure that no rules like this crop up again. 

I do suspect there will be some changes in vehicles to make them a little less durable, which will cause melta to fall out of style (perhaps not completely, but changes would assuredly cause plasma weapons to become more attractive options).  

Plasma has dominated the game in the past and has been nerfed into oblivion since.  It’s slowly making it’s way back, but I don’t expect they’ll bring it back full force a la 2nd edition.  Whatever changes are made to the weapon, I expect them to be subtle.  

What do you think?