Talk:Gauss Cannon

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This weapon is outrageously profitable to manufacture, paying back your entire investment in about 33 days and then proceeding to return 1100% return on investment - basically doubling your money every month if you re-invest in Gauss Cannon manufacture. So describing it in the main article as "quite profitable if you have some idle time" is a bit of an understatement!

Ammo Manufacturing

Interesting point about submarine Gauss Cannon ammo: Clearly there is huge demand for this weapon, with the world's navies queuing round the block to pay through the nose for them. And yet the absolute maximum world production of ammo for this weapon - that everyone is buying - is less that 200 rounds per day (due to the manufacturing limit of only one item of each type per hour per base). Given all the Gauss Cannons the world's governments are buying, the laws of supply and demand would dictate that Gauss Cannon ammo is the most profitable item in the game! Sadly not, of course, the ammo changes hands for no more that the price of its raw parts, without any return for labour or investment. Not only are the governments not interested in actually firing these weapons, they don't even seem to want to load their magazines!

By the way, because of this manufacturing limit, if you ever contemplate using Gauss Cannon yourself on aircraft or in tanks it's wise to assign up to 5 technicians - no more - in each base to be permanently making Gauss Cannon ammo. Each base will manufacture 24 rounds a day (from 5 Techs), which hopefully will be enough for your needs.

Cost of Operation

As the main article states, the main drawback is the ammunition production. Given the performance characteristics above, you would think it might be worthwhile to allocate 5 technicians per base to manufacturing Gauss Cannon ammo full time, to have a reasonable amount of ammo in stores. To get the true costs you must consider the opportunity cost of manufacturing Gauss Cannon ammo. If you can make Gauss Cannon ammo, you can make Gauss Cannon. Technicians who are making Gauss Cannon will gross you nearly $100/hr. Therefore Technicians who are diverted to making Gauss Cannon ammo cost you $100/hr in foregone cash. This pushes the cost per round from $200, to about $380 including labour, to around $877/rd including opportunity cost (including Gauss Cannon lost from the extra 2 Workshop spaces used for ammo).

However, even taking into account the opportunity costs of manufacturing the ammo, the Gauss Cannon is about 4 times cheaper in ammo consumption per point of damage delivered (compared to the DUP).

Combat Effectiveness

I think this weapon is perhaps under-rated. It actually has twice the firepower (average damage per second) as the DUP Torpedo, with about 6 times the total payload (total damage dealt). Let me say that again: twice the firepower, six times the payload. That's worth thinking about.

Obviously the lower range is a serious disadvantage, but if you absolutely wanted to down a Large USO, on a potentially one-way mission (with multiple craft hopefully), dual Gauss Cannon could actually be much better than dual DUPs. And it does have stand-off advantage on 2 USOs, the Escort (Small) and Hunter (Medium). So it might be worth keeping one around.

The XcomUtil "improved weapons" version is probably more useful. With the increased range of 36km, it can stand-off against all Small and Medium USOs. To compensate, the damage (and payload) is halved, but this still makes the firepower (damage per second) roughly the same (94%) as the DUP Torpedo, and 3 times the payload.

The higher payload means the craft armed with Gauss Cannon can perform multiple successful engagements before re-arming - as much as six times as many successful intercepts, if there are targets available. Also, the arming rate is at least 3 times higher than missile-armed craft, thus it returns to alert status up to 2 hours earlier than a missile-armed craft. (By the way, can anyone confirm the actual reload rate, I'm assuming it's either 50 or 100?).

The payload also comes into play vs bigger targets, where the total payload of a pair of DUPs is similar to the damage capacity of the USO. This means there is a signficant random chance of failing to shoot down the USO and breaking off empty-handed. With a pair of fully loaded Gauss Cannon, you have enough damage capacity aboard to down 4 Medium USOs or 6 Small USOs on average. And whereas you need 2-4 DUP-armed craft to have any realistic chance of taking down the Large USO, a single Gauss-armed craft has a good chance of taking down any Large USO - provided it survives long enough. Attack with multiple craft of course, to increase your odds and reduce the damage taken.

The Gauss Cannon also delivers its damage more continuously and more predictably (with less random variation) than the DUP Torpedo or other missile weapons. It also suffers much, much less than missile weapons from the "Last Shot Misses" bug, which can effectively be ignored for all cannon-type weapons. This means you don't have to remember to switch to Aggressive to avoid wasting your last shot, as you do with missile weapons.


The lower range is the obvious drawback, meaning fewer USOs can be engaged Cautiously at a safe stand-off range.

DUP Torpedos do have the benefit of a bigger initial "shock" from the first hit. It still takes several hits to kill, so I'm not sure that is any advantage. However it may be that USOs find it easier to break off if the damage is coming in small continuous amounts rather than large random amounts - that needs some testing.

Of course a single standard craft weapon load across the fleet is more cost effective than maintaining a mixed fleet. So if you don't want to tackle the larger USOs using Gauss Cannon, it might not be a practical strategy. Due to the long delays in arming craft, it's not usually feasible to rearm a craft after the threat is detected. Non-stand off attacks are very costly to make in terms of repair time, during which time your interceptor craft are not available, not to mention total loss of the craft and weapons. Large craft do tend to linger, so you might have time to arm up with DUPs (4 hrs plus?). If they are Battleships or Dreadnoughts and you really have to attack them, Gauss Cannon and Aggressive attack might be the better option anyway. But in order to avoid having to match interceptor craft to targets, and to avoid maintaing a mixed fleet or rearming on the fly, you might want to stick with DUP Torpedos after all, until Sonic Oscillators are available. These are the clear winner overall in craft armament, no question about that.


In conclusion it is worth considering arming at least some of your craft with Gauss Cannon when it becomes available, whether you use XComUtil or the standard game. If you use XComUtil "improved weapons", use Gauss-armed craft against all Small or Medium USOs. Use them against Large USOs if you wish to engage them. If you do not use XcomUtil "improved weapons", you may want to identify the craft before attacking. If it is not an Escort or Hunter, break off, or do an Aggressive attack and be prepared to take damage. If you decide to engage large USOs, also go Aggressive and be prepared to take damage, but your attack will probably be more effective than an attack with DUPs would have been.

Last thought - if you do use Gauss Cannon on your subs, be careful having any Coelacanth/Gauss tanks in the same base, or they will steal your precious ammo!

Spike 09:00, 11 October 2008 (CDT)

The main things I see as the advantages for the DUP head is a longer range, a much higher accuracy, and the ability to purchase the weapons on the open market without having to tie up Workshop space. However, I will need to see about giving the XCU Gauss Cannon a second try. Also, for future reference, the damage inflicted by a craft weapon is 50%-100% of it's listed damage; an average damage would actually be 75% of listed. UFOs/USOs use the same calculation to determine if they're destroyed or shot down/grounded; if they take more than 50% of their listed damage capacity in damage, they're shot down, but if you break 100%, they're destroyed. Arrow Quivershaft 09:14, 11 October 2008 (CDT)

Comparison vs Ajax

I don't agree with the main article's unfavourable comparison with Ajax. Even at the high opportunity cost I gave above, of $877/round, this is 4 times cheaper than Ajax rounds, for only 75% of the average damage per round, with 8.33 times the number of rounds carried, for 6.25 times total payload (average damage delivered from fully expended magazine). The firepower (damage per second) is also much higher. The exact value depends on what RoF numbers you believe. Based on USOPaedia values of 4 vs 17, the Gauss Cannon firepower is 3.1875 greater. My empirical research on RoF suggests an RoF ratio of 6x in Aggressive, 9x in Standard, 12x in Cautious, giving firepower ratios of 4.5x / 6.75x / 9x in favour of the Gauss Cannon. This means the Gauss Cannon will empty faster, doing more total damage, than Ajax. The Gauss Cannon will also reload slightly faster at base than Ajax, giving a better sortie rate / higher readiness percentage.

Against this, all Ajax has that Gauss Cannon doesn't have is stand off advantage against one USO type, the Heavy Cruiser, and stand off advantage can't be used in Aggressive mode of course. Plus an extra 12km that a craft armed with Gauss Cannon is exposed to enemy fire before it can return fire. An Ajax armed craft could fire maybe 1 extra Ajax in the time it takes the Gauss Cannon-armed craft to close into firing range. That goes by very quickly, and is more than made up for by the vastly increased firepower and payload of the Gauss Cannon.

Unless you are encountering nothing but Heavy Cruisers, I don't see any case for mounting Ajax over Gauss Cannon. Even then, the Ajax plus Gauss Cannon combo would probably be more versatile and definitely more powerful overall, than dual Ajax. More realistically, replace all Ajax with Gauss Cannon. How nice for a research-and-developed human weapon to actually be superior to its predecessors!

The case against DUP is not quite so clear. While firepower is 2x to 2.5x greater, and payload around 6x, the stand off advantage and first-shot shock power of the DUP are pretty compelling. Also the DUP, somewhat oddly, has a faster turnaround cycle than Gauss Cannon (or Ajax) - 3+1 hrs per launcher, vs 5+1 per for Gauss Cannon, 6+1 per for Ajax. Still, I would say it's a least worth switching from dual DUPs to a DUP-and-Gauss-Cannon combo.

NB for the XComUtil-modified Gauss Cannon, firepower is halved, but range is increased to greater than Ajax, so there really is no case at all for using Ajax. Of course, the reduced firepower weakens the case vs the DUP. Personally I don't like the XComUtil mod to Gauss Cannon (or Laser Cannon) any more.

Anyway, unless anyone objects, I'm going to tone down the main article in the light of the GC vs Ajax points here, and the GC vs DUP points above.

Spike 19:34, 12 October 2010 (EDT)

Go ahead and change the article Spike. This is one of those throwbacks to before the NPOV era. I'd rather see a more objective view on the Gauss Cannon as well - explain its merits and point outs its weaknesses rather than outright saying it sucks. Perhaps much of the old article should be moved to Weapon Analysis. -NKF 01:10, 13 October 2010 (EDT)
Agreed. I was thinking the same thing, move it to a Compare X vs Y article in Weapon Analysis. And actually I may have spoken to soon on this. I'm taking on faith that the published reload rates are correct. Of course, for EU, the published reload rates are just plain wrong. Using the published rates led me to be over-enthusiastic on the Laser Cannon. My comments above assume there's a 3::4 rate of fire ratio between Gauss Cannon::Gas Cannon. But if TFTD uses the same code for this as EU, the rate of fire ratio is more likely to be 2::12, which is 4.5 times worse. Which would kind of invalidate all my claims above about superior firepower! Anyway I'll do some "Cannon Timer" tests ("Gas Cannon Timer" in fact) and find out the empirical rate of fire of the Gauss Cannon. Spike 05:37, 13 October 2010 (EDT)
Oh well. Tests show that the Gauss Cannon has 6x slower Rate of Fire than the Gas Cannon, exactly like the Laser Cannon which has 6x slower RoF than the Cannon. So, relative to the Gas Cannon's Reload interval = 3 gs (game seconds), the Gauss Cannon's Reload interval is more like 18 gs rather than the stated 4 gs. Why did the TFTD designers even bother to change the Reload Rate stats, when those stats have absolutely no effect on actual RoF? Is it possible they did not realise that the Reload rates in the executable are not used? I had hoped that this had been fixed in TFTD, but I guess not. The firepower statements above will need to be edited, based on the empirical RoF. GaussC::Ajax RoF ratio is 24:18, not 17:4. GaussC::DUP RoF ratio is 36:18, not 21:4.

Empirical Firepower Comparisons

Based on empirically tested rates of fire, so far TFTD craft weapon firepower looks like:

  • Gas Cannon 15 x 25% / 3 = 1.25 dmg/gs
  • Ajax 60 x 70% / 24 = 1.75 dmg/gs Aggressive; 1.16 Standard, 0.875 Cautious
  • DUP 110 x 80% / 36 = 2.44 dmg/gs Aggressive; 1.63 Standard, 1.22 Cautious
  • Gauss Cannon 90 x 35% / 18 = 2.625 dmg/gs

(The data for total payload are unchanged, cannons are clear winners on total payload)

So from this data there is still a strong argument for picking Gauss Cannon over Ajax. Gauss Cannon vs DUP is a much more finessed judgement.

Ammo Type

The game has data for two ammo types both called Gauss Cannon Ammo. Only the first type (at 0xD0 in BASE.DAT (TFTD)) is used. This is the lighter, cheaper ammo which was perhaps originally intended for the SWS Gauss Cannon. This type is in fact used for both the SWS ammo and for the craft ammo. The second type (at entry 0xD2 in BASE.DAT (TFTD)) is believed to be unused.

The second type can be unlocked using game editors such as XComHack or XComUtil.

The characteristics of the two ammo types differ significantly.

Entry  Intended?  Actual   $  Sell  Space
 0xD0  SWS        Both     $   200  0.1
 0xD2  Craft      Neither  $53,300  0.6

If unlocked for production, the 0xD2 ammo type enables massive, game-changing profitability.

Experiment re Base item 0xD2

  1. Added 200 rds to what XComHack calls "Coelacanth GC Ammo" (item 0xD0)
  2. Added 100 rds to what XComHack calls "Craft GC Ammo" (item 0xD2)
  3. Both are reported as "Gauss Cannon Ammo" in Base Stores
  4. 200 rds using Space 20, sell at $200, is listed first, sounds indeed like SWS ammo (lighter, cheaper)
  5. 100 rds using Space 60, sell at $53,300, is listed second, sounds indeed like craft ammo (heavier, costlier)
  6. Equip Sub reports 200 rds available for Craft Gauss Cannon
  7. Hence it is using the SWS ammunition also for Craft Gauss
  8. After moving Coel/Gauss to Triton, base stores reports 150 rds
  9. Also Equip Sub now reports 150 rds. Pretty conclusive.
  10. After equipping the Sub with Gauss Cannon, at the top of the hour,
  11. Equip Sub reports 10 rds loaded, Base stores report 140 rds / 14 space left of the presumed "SWS" type ammo.
  12. And still full 100 rds / 60 space of "craft" type ammo.


  • Craft type ammo is not used. Both craft and SWS use the SWS type ammo.
  • SWS/Craft ammo sells for $200/ea. Original Craft-only ammo would sell for $53,300 ea.

Spike 17:12, 24 September 2012 (EDT)

I just wish that this weapon wasn't completely useless. It is the best looking craft weapon, whereas the Sonic Oscillator has much worse art; I wish the artwork was switched around. -Harry Robinson 21:07, 10 February 2018 (EDT)