So, our group was looking over some of the weaponry for a terminator and one of my players came to this conclusion...

A storm bolter is a better weapon (more shots and more damage) than an assault cannon.

Now, please keep in mind that he has never played any other 40k game at all (either RPG or tabletop). To the opposite extreme, I have played 40k tabletop since 1992 and have played DH and RT. His comment made me wince. I asked him to explain.

Here is his math (I don't have my book on me right now so a few of my numbers may be slightly off, but not by much):

Example BS = 50 (+20 for full auto)

Assault cannon can only fire on full auto, so let's compare that.

Assault cannon full auto = 10 shots. Each hit does 3d10+6 damage (averaged to 22.5 excluding Righteous Fury)

Storm Bolter full auto = 4 shots + Storm trait. Each hit does 2d10+5 damage (averaged to 16 excluding Righteous Fury)

So, with an attack roll of 69 (success, with no degrees of success)...Assault Cannon does 22.5 and the Storm Bolter does 32 (because of two hits from the storm)

Attack roll of 40...Assault Cannon does 67.5 damage and the Storm Bolter does 96.

Attack roll of 30...Assault Cannon does 90 and the Storm Bolter does 128 (its maximum fire rate)

Attack roll of 20...Assault Cannon does 112.5 and the Storm Bolter still does 128.

Attack roll of 10...Assault Cannon does 135 and the Storm Bolter still does 128.

So, the assault cannon becomes advantageous at an attack roll of 10 or less. Is there something I'm missing? Knowing that tabletop game, the assault cannon has twice the firing rate of the storm bolter. It seems that an easy fix would be to give the assault cannon the "storm" trait. The storm trait does describe multiple barrles shooting and the assault cannon is six spinning barrels.

Anyone have any ideas or comments?

Yes, give the Assault Cannon the Storm Trait, it obviously needs it...

Yep assault cannon needs 'Storm' alright, otherwise there's a whole thread on the main page (well numerous threads) about Bolters being overpowered.

That's what our group did as well.

We dropped the range of the Assault Cannon from 150m to 100m since its range TT is equal to a regular Astartes Boltgun. We then gave it the Storm Quality because we felt it works better as a "volume of fire" weapon. This also keeps it a little more distinct from the Heavy Bolter.

Imo the weapons are strong enough as is. I´d rather nerf the storm bolter than buff the assault cannon.

I´d just take a normal bolters stats and double its rate of fire to S(2)/4/8 with single shots scoring 2 hits with one or two DoS. Problem solved.

Well part of your comparison lacks the reduced damage from toughness and armor. If you use against another SM with 16 damage reduction then the assault cannon will be doing a fair bit better than the storm bolter in your damage comapisons.

"So, with an attack roll of 69 (success, with no degrees of success)...Assault Cannon does 22.5 and the Storm Bolter does 32 (because of two hits from the storm)" instead becomes about Assault cannon does 24.467 with tearing, no RF calculated, and Storm Bolter does 18.475 * 2 with tearing, no RF. If on another SM with 16 armor and toughness then each shot is reduced making them more like: Assault canon ~15 over armor and toughness, and Storm Bolter ~ 7.5 * 2 = 15. This makes them about the same. You have a higher maximum with the assault cannon though. Also, without RF you are going to roll a lot of non-damages with the storm bolter.

Basically the difference isn't as far as you initially put forth, although it also doesn't make the assault cannon look better than the storm bolter, but about equal. There are also many more circumstances that make the storm bolter look better (less armored foes) and look worse (more armored foes, terminators and such). Maybe just increase the penetration of the assault cannon or give it the felling trait.

Suijin said:

Plus, the problem isn't just wounding marines. The problem is killing them, which means giving a marine with depleted wound points a hard enough hit that he dies or gets put out of action in spite of True Grit (I have to keep raising this talent). Doing 5 points of damage coming through won't do. More like 10 to 18 points need to pass through Toughness and Armor.

Alex

It was mentioned in another thread that adding Devastating and Felling, instead of Storm, to the Assault canon could make it more palatable.