Autocannons and Ammunition

12Aug08

One of the things that my last few frigate fights have got me thinking about is the question of autocannons and ammunition. The most common fit that I have been using is three 150 mm Light Autocannon IIs loaded with Barrage ammunition. This gives me good range should my target not want to orbit at my preferred range of 500 m and good tracking despite the penalties of using Barrage ammunition. But is this the best combination? In order to investigate I started to run some numbers and here’s what I found out.

Because I’m doing this for my own benefit I’ve run the numbers based upon my own style of fighting and skills rather than a more abstract approach.

First of all lets imagine that I’m in a Rifter fitted with a microwarp drive, 400 mm Reinforced Rolled Tungsten plate, and Damage Control II. In this case I use my microwarp drive to close the distance on my target and try and hold a close orbit at 500 m using a web to pin down my target. My maximum speed in this arrangement is 384 m/s so lets take the transversal velocity as 400 m/s and the range as 500 m. For the sake of this test I’ll fit my ship with 150 mm Light Autocannon IIs.

From this graph you can see that under these conditions my optimal range is 2000 m and that Replublic Fleet EMP ammunition does the best damage. So next time I engage someone should I set my orbit to 2 km and load up the EMP? Well, its not quite that simple. What happens if I’m up against an armour tanked Rifter? Lets put in the basic armour resistances of a Rifter and see how that effects the damage.

Now we can see that the most effective ammunition for a close-up fight isn’t one of the high tech ammunitions but Republic Fleet Fusion. At this speed the tracking penalties for Barrage and Hail mean that it just doesn’t do the job as well as regular ammo does.

But this still isn’t the whole story. Even if I go fast enough to dictate range my opponent may still effect the transversal velocity. And what if he has a web? Then my speed will drop right down. Will that affect the ammo I should use? Let’s have a look.

In this graph we can see what happens as the transversal velocity changes while still holding an orbit of 2 km around my target. At all speeds Republic Fleet Fusion is better than Hail, although only just when we’ve been webbed. This leaves me with one last question. Is 2,000 m still the best range to orbit at if I suspect my opponent has a web? Especially against cruisers I want to get in under their guns as much as possible. Let’s revisit our first plot but this time with a transversal of 40 m/s assuming both ships are carry 90% webs.

In this case we can see that Hail is a far superior choice of ammunition for the job, although Fusion still packs a hefty punch. Now, rather than my previous optimum of 2,000 m I can do the most damage closer in at about 750 m so I should set this as my optimum.

Thankfully when facing shield tankers this problem is vastly simplified by the fact that there is only really one choice of ammunition, Republic Fleet EMP, so this choice is already made. There are still questions about default orbits to deal with but that’s about it.

As well as my own ammunition I also need to consider what my opponent is most likely to be carrying. Against missile ships the tactic is very simple; go as fast as possible at your optimum range. It is speed not distance that will defeat missiles. Blaster boats are a bit different, though. Let’s consider a Gallente Tristan with Light Neutron Blasters II and Void ammo. With maximum skills his optimum range is 1.7 km and his falloff is just 1.3 km so if I orbit at 5 km he will barely be able to hit me while I can pound him with Barrage out to 10km and beyond. My best approach, then, is probably to use Barrage and orbit at 7 km so I can hold him in warp scrambler range. If I want to go in close I can also get in under his tracking and load up Fusion like before.

What about a Punisher? Well, fitted with Medium Pulse Laser IIs and Conflagration ammo they have an optimal of 3.8 km and a falloff of 2.5 km. In this case it is much harder to out-distance their guns, even using Barrage. Instead we can exploit their tracking, which is terrible. Load up the Republic Fleet Fusion and get in close. This is especially effective because he can only pick two midslot modules so is unlikely to have stasis webifier fitted.

Conclusion

So what have I learnt from this exercise? Well, basically that I have been misusing Barrage. Its purpose is to orbit outside of your opponents guns so its uses for my ‘orbit at 500 m’ tactic are limited. Instead I should use Republic Fleet Fusion when I don’t think my opponent has a webifier and Hail when I think he does.

There is one other question left to answer. That posed by Burn Mac in his response to my post about passive and active tanking. What is the effect of changing the size of the gun? Are big guns better?

Well it actually happens that the effect of the size of the gun is pretty minimal. When using ammunition with tracking penalties or high transversal velocities smaller guns will help you hit your target more often. You’re better off not sacrificing the rest of your set-up just to fit larger guns. Small guns and gyrostabiliser do more damage than bigger guns without one.

Of course, all of this changes when I consider what happens if I fit an afterburner and use that during combat but that discussion is for another time.

References

The formula used to calculate the DPS for the various combinations comes from Naughty Boy via Scrapheap Challenge. There is also a good discussion of autocannon tactics in The Rules Of Autocannons but I think a lot of this applies only to cruiser-sized ships and above.

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8 Responses to “Autocannons and Ammunition”

  1. 1 Burn Mac

    Absolute gold, ive been thinking about running the calculcations earlier before and going for RF Fusion earlier but never got to calculating it and here it is all done for me and even my question about gun size is handled, amazing! Thank you so much.

    On a side note since im still a n00b i havent had the skills to fit mwd so when i hit orbit i am perm running my ab giving me a faster orbit, according to these calcs my tactics will just further discourage the use of Barrage or EMP unless i just hit approach and tries to minimize transversal.

    On a sidenote i think most Punisher pilots fit 3 x DLP II and packs eiter conflags and scorch or Amarr navy multifreqs and amarr navy microwave crystals,(to be able to track, and again DLP:s have better tracking than MPL:s).

    Other than that i wis i whould have 4 hands so i could give this post 4 thumbs up!

  2. 2 Burn Mac

    its suppose to be Barrage or Hail..

  3. 3 Wensley

    I am planning on redoing the calculations with an afterburner at some point too. Now I’ve got the script written its very easy to put in new numbers for ship, guns, and ammo.

  4. I guess this should be a total side note, but why not fit 200mm autocannons on the ship?
    A lot of the instances the Rifters that take me on have that fitted with EMP smalls, 1 microwarpdrive, and the rest of the armor tank.
    Loving the detailed analysis though!
    Adding you to my blogroll, keep up the good work.

  5. 5 edrayne

    @ Tony: Basically just because I can’t fit them and the actual DPS difference by the time you’ve considered tracking is pretty tiny

    Thanks for adding me, I already follow yours 🙂

  6. Oh I see.
    Cool, thanks. I’ll check back in often!

  7. 7 Graeme

    Out of interest, what did you use to do you graphing?

  8. 8 wensley

    I wrote a python script to do the calculations and let matplotlib do the graphing.


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