Meltagun Math-Hammer

[minigun762]

EDIT: Bannus and Cornishman smarter then I am :) all values are correct now

I wanted to know how reliable it really is to use close range Meltagun spam squads for anti-tank (like the Chaos Termicide), so I ran the numbers and here is what I got.

Formula against AV14 (worst case scenario)

1 Melta shot @ BS4 = 0.667 hits x 21/36 (chance to roll atleast a 7 on two dice) = 38.9% chance of penetrating hit.

 

Here is an extended chart with 1-6 Melta shots fired and the probability of getting atleast 1 penetrating hit:

 

1 = 38.9%

2 = 62.7%

3 = 77.2%

4 = 86.1%

5 = 91.5%

6 = 94.8%

 

What does twin-linking do to this?

 

Twin linking would increase the chance to hit from 0.667 to 0.889. So the new formula would look like this:

1 Melta shot @ BS4 = 0.889 hits x 21/36 (chance to roll atleast a 7 on two dice) = 51.9% chance of atleast 1 penetrating hit.

 

1 = 51.9%

2 = 76.9%

3 = 88.9%

4 = 94.6%

5 = 97.4%

6 = 98.8%

 

So if you use 2 you have a very good chance of getting 1 penetrating hit. 6 would statistically wield 3 penetrating hits and so forth. That's why I prefer just figuring the number of penetrating hits you are likely to score :) .

 

Ironwind has a good point, if you want quick and dirty method, just do this:

3 shots = 2 hits = 1 penetrating hit

As you see its not quite accurate, as you will actually completely miss once per four attempts, but its good for a quick check.

Remember all these numbers are compared against AV14, so you can expect better results against weaker armor.

[Gornall]

What does twin-linking do to this?

[Bannus]

4 = 93.8%

5 = 96.9%

6 = 94.4%

 

 

You may want to recheck your numbers.....:D

[minigun762]

4 = 93.8%

5 = 96.9%

6 = 94.4%

 

 

You may want to recheck your numbers.....:D

 

EDIT: Nevermind, I got the point. I fixed the original post.

 

What does twin-linking do to this?

Twin linking would increase the chance to hit from 0.667 to 0.889. So the new formula would look like this:

1 Melta shot @ BS4 = 0.889 hits x 21/36 (chance to roll atleast a 7 on two dice) = 51.9% chance of atleast 1 penetrating hit.

Assuming my math from above is correct, the new chart would be:

1 = 51.9%

2 = 76.8%

3 = xxx%

4 = xxx%

5 = xxx%

6 = xxx%

[Grand Admiral Thrawn]

I think he means you got the percentages mixed up for the 5 and 6.

[IronWinds]

I think Bannus was pointing out that 6 shots have less of a chance of doing anything than 5 shots. Either we have marines shooting each other or the math has an error.

 

 

And it probably isn't a good idea to use percentages.

 

Don't think of it as .5 being 50%. Think of .5 being a high probability that you'll score .5 penetrating hits. So if you use 2 you have a very good chance of getting 1 penetrating hit. 6 would statistically wield 3 penetrating hits and so forth. When you do the percentages for firing 6 you aren't really doing the statistics of how many penetrating hits your likely to get... at that point what you are really doing is calculating the 'inverse' of the chance that you score 'no' penetrating hits at all. So you have something like a 6% chance of doing nothing with 6 shots. That 94% chance isn't that you penetrate it, its a 94% chance that you penetrate it AT LEAST once. That's why I prefer just figuring the number of penetrating hits you are likely to score :D .

[Cornishman]

Erm I think you'll find the odds of rolling a 7 or more on 2D6 are 21/36.

 

So giving

1=0.39

2=0.63

3=0.77

4=0.86

5=0.91

6=0.95

[minigun762]

Erm I think you'll find the odds of rolling a 7 or more on 2D6 are 21/36.

 

So giving

1=0.39

2=0.63

3=0.77

4=0.86

5=0.91

6=0.95

 

Grr yes you're correct, I don't know where I got 27/36 from, sorry about that.

 

Thats what you get for doing quick math at lunch.