The Math of the Missile Launcher

I'm not sure how many times I've heard someone say something like "yeah, but 4 missile launchers in one devestator squad is overkill for killing vehicles, you only really need 2 or 3 per squad, max."  I DO know that if the number of times I've heard that said is 'x', then I've been annoyed x times. 


I'm not exactly sure what the math of missile launchers being able to pop rhinos and chimeras, but I DO know that my single missile launcher I used to use as a Blood Angel player in the old codex never really seemed to do something.  If it popped a transport, or even just stunned it for a turn, I was happy for the game.  In 5th edition, you need to be able to pop tanks, and with the new Blood Angel Codex out with cheap devestators, I've made it my mission to see if they're going to be the answer for me.

So let's dive right in:

If I have 4 Missile Launchers in my Dev. squad and they all hit, there will be 2.66 hits total.

So, if they shoot at a Rhino:

2.66 hits
1.332 penetrating hits
.44 glancing
Results:
.44 destroyed results from penetratings
.14 weapon destroyed/immobilized results from glancing

So, less than 50% chance to kill a rhino that DOESN'T have a cover save.  If it has a cover save, cut those results in half.

If they shoot at a Chimera (front AV 12):

2.66 hits
.88 pens
.44 glancing
Results:
.2955 destroyed results from pens
.14 weapon destroyed/immobilized results from glances

So, with a squad of 4 missile launchers, it's less than 1/3 shot at destroying a chimera.  Hardly overkill, if you ask me.  And that's again assuming they don't have smoke or cover.  These are the same odds of destroying a Wave Serpent if it hasn't turbo-boosted.

How about vs. an ork Trukk, or Dark Eldar Raider (open topped)?

2.66 hits
1.77 pens
.44 glances
1.18 destroyed from pens
.22 destroyed, immobilized, or weapon destroyed from glancing

Better, but still no sure thing, especially if they're in cover.

In the end, I think that missile launchers, if they're going to be used to full effect, need to be used in squads of 4.  Four launchers barely cuts it against rhinos (who will usually have their cover saves the first and most important turn) and against a chimera, you're more trying to halt their mobility than really kill it. 

So please, in the future, please don't say that 4 launchers is overkill- you've already spent 120 points on the squad to accomplish a task, you may as well spend another 10 make sure you finish the job.