40k Simulation Center – Big Bugs with Big Guns

Long time no see! I apologize for not writing more, but life has been crazy and balancing hobby time has been difficult. I bring good news for the future though! Now that this article is posted, it is time to strip down by 10 year old computer and build a new one (long overdue!).

I’m hoping this will enable my simulation time to drop or allow me to try much bigger simulations without decreasing the number of iterations. Simulation time can vary wildly depending on how many shots/attacks and different forms of rerolls and other buffs need to be hashed out. Each set of full rerolls can increase the number of rolls I have to go through by up to a factor of 2 in the worst case and only gets worse the more rerolls, exploding shots, etc I have to consider. Unfortunately, I only have so much time each night to sit and hobby so I’m hoping some speed increases will simply help me get through my brute force approach a bit faster.

This week I want to examine the Tyrannofex and Exocrine with a focus on cracking vehicles…namely Redemptors (classic for my work) and hot on the scene again: an Imperial Knight with rotated ion shields. These types of comparisons are fun because the variability can be quite high and the distributions fun to look at. While Tyranids have more than enough tools to crack anything with a variety of other options, let’s take a look at what would be considered in other codices very good units.

Guest Writer: Dan Meyer

While playing test games is the best way to understand your options, it’s hard to get in enough games to understand all the variables at play and arrive at a reasonable set of expectations. Have no fear though! I am here to help by giving you an in depth look at what you should really expect out of a unit or piece of wargear.

My Shtick

I will look at a unit and their wargear options and help you understand what is the best choice for a given situation or at least help you figure out what you can truly expect from your units. I achieve this by simulating 1,000,000 iterations of that unit attacking a set of common targets that are representative of things you will see in the meta and get a true sample population so we can not only understand the mean of the expected outcome, but also how the variance shapes the outcome distribution. This will give you a much better appreciation for the variability in your game. If you have any questions on my process, ask away!

Tyrannofex vs. Exocrine!


The new Tyranids bring a ton of tools to the battlefield and can layer a complex web of buffs and abilities that are truly quite horrifying to behold. For this analysis though, we won’t have too many buffs to consider and I want to keep this a nice simple comparison. The Tyrannofex runs a cool 190 points with the Rupture Cannon and the Exocrine runs a solid 170 points. I feel like given the stats and gun power these guys are toting around, the points are very, very reasonable, especially the Exocrine.

Unit and Wargear Breakdown
Tyrannofex Rupture Cannon3144D6+4
Exocrine Bio-plasmic Cannon6+D3843Blast

At a first glance, we see the Tyrannofex brings a low shot count, but high powered cannon capable of 30 damage if you are ultra-lucky. The exocrine gives up on pure power and damage and settles for having far more shots with a max output of 27 damage. This is a fun trade off to look at and I actually praise GW for finally making choices that are similar actually interesting to consider. Albeit, I think generally I would choose the exocrine at first glance simply because more shots is more useful against a wider array of targets than just vehicles and it’s cheaper. But let’s find out together how they stack up.

For these analyses, we will one condition for the Tyrannofex and two conditions for the Exocrine:

  1. Baseline Tyrannofex
  2. Baseline Exocrine
  3. Exocrine with Observer Organism Stratagem

The Exocrine actually has access to its very own personal stratagem: Observer Organism for 1 CP. This strat makes your target not receive the benefits of cover (which it gains simply by standing still……seems pointless) and gives the Exocrine unmodified hit rolls of 6 cause 1 additional hit. This is a fantastic stratagem considering that you will have somewhere between 7 and 9 shots base. This puts the theoretical upper limit of damage at 54. This will never happen essentially, but we can expect a nice upper in the damage output.

Let the Simulation Begin…

First, let’s take a look at the Tyrannofex!

Figure 1: Tyrannofex with Rupture Cannon vs. Variety of Units

This is the sort of reason why I made my simulation code. High variability with enough randomness to make the distribution less obvious without some thought! First off we note against the Redemptor, the
-1 damage makes it so our floor (besides 0) is 4. I actually manage to record the max damage possible (27 due to the -1 damage) 27 times out of a 1,000,000 iterations. On average you are looking at 9 wounds with the most common single output being 0 damage dealt. I’d also like to note that it’s very interesting that we get such a weird shape in the distribution. This is because the -1 damage is interacting with a variable damage weapon with only 3 shots!

Against the Knight, the results are pretty abysmal. Thanks to the low number of shots, the invulnerable save has good opportunity to knock down whatever manages to hit and wound. Almost 50% of the time though you will do 0 damage. Living on a coin flip sucks, let alone that the chances of doing more than 10 damage are less than 13%.

Now let’s take a look at the baseline Exocrine.

Figure 2: Exocrine with Bio-plasmic Cannon vs. Variety of Units

First thing we can clearly see is that our distribution shape has become more normal. The higher volume of shots means we trend away from odd looking distribution shapes.  Against the Redemptor we do significantly less damage on average; however the chance of doing 0 damage is less than 5%. The chances of outright killing a Redemptor are also very small thanks to the -1 damage and the benefits of the armor of contempt rule! Against the Knight, we lose out on average to the Tyrannofex, BUT we gain far more reliable output where we have cut the chances of doing zero damage almost in half comparatively. So far the tradeoff is very interesting: the Tyrannofex on average does more damage with a better ceiling but at the cost of being less reliable than the Exocrine’s output. Let’s see what happens when we pop Observer Organism and see how much that helps out.

Figure 3: Exocrine with Bio-plasmic Cannon and Observer Organism vs. Variety of Units

Adding exploding hits helps out against the Redemptor, but only pulls up the ability to kill one outright to about 5%. Against the Knight we get a tiny boost up to 5 damage of average while further lowering our chances of doing 0 damage by about 5 percentage points. I really like the Exocrine overall and while not good at taking out Knights, can surely help damage plenty of other vehicles and units in the game. 

Well there you have it! The battle of the big bugs with big guns is over. The conclusion? If you are solely needing something with the intent to kill vehicles, I think the Tyrannofex is actually more compelling of a choice than I imagined, but will be very swingy. The Exocrine specifically did not shine against the Redemptor because of the -1 damage and required a stratagem to meet the same average as the Tyrannofex against the Knight, albeit reliably ensuring damage due to higher volume of fire. In the end, I would still pick the Exocrine because it saves 20 points with added benefit of being good against a variety of other targets. What do you think?

Let me know if you have any questions, comments or concerns with any of the results you have seen here! And of course, I welcome all suggestions for future simulations!

The Emperor Protects,



About Matt Castro

Matt, also known as MagikarpUsedFly, is a video game and 40k youtuber and streamer. Based in California, Matt has been playing 40k for over 3 years and has been making content for the game for a little over 1 year now.
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22 days ago

Man it’s crazy how the dx+y flat damage buffs make these guns so much more reliable.

It’s not even meta but I can’t imagine not taking the big guns. Telling how these are so strong and STILL not being used

Thomas Covenant
Thomas Covenant
20 days ago

Yeah I wouldn’t consider a RuptureFex outside Leviathan (for the inherent rerolls). Even then I’d rather have the Exocrine. Leviathan Heavy Venom Cannon spam is a really good list, utilizing a Walkrant with Shardgullet, two Harpies and lots of Carnifexes with HVC’s, Enhanced Senses and Talons.

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