Coilgun BP costs


Homebrew


After comparing the different light starship weapons it seems that the coilgun is too good to be true:

Coilgun Long range, average 10 damage (min: 4, max 16) per hit and costs 6 build points. 1.67 damage per BP

We can compare that to two other weapons that also have no special properties and have similar damage output:

Light particle beam Medium range, 10.5 damage (min: 3, max 18) for 10 BP: 1.05 damage per BP and shorter range.

Twinlinked light laser cannon Short range, 10 expected damage (min: 4, max 16) for a minimum of 8 BP: 1.25 (or less) damage per BP, shorter range and uses two mounts.

In my opinion these three options should be similar, with players really having to choose between the options. I would expect that with longer range comes lower damage output per BP. This is currently not the case.

Therefore I am seriously considering to increase the costs of coilguns to 10 BP. That would set their damage output per BP at 1.00, which is slightly lower than the light particle beam. The advantage of a coilgun is the longer range

You can take a look at the key figures here, I am curious to see what your thoughts are on the subject.

Edit: I should probably have posted this in homebrew or rules.

Sovereign Court

Yeah, I'm one of his players. Yesterday we were looking how to refit the Sunrise Maiden and were surprised at how much better the coilgun looked. We were wondering if there was some mistake or something we hadn't noticed.

Silver Crusade

Its definitely one of the superior light weapon choices by far. I feel like the BP isn't even that bad but feel like a better balancing factor would be PCU cost. Honestly, you could probably do both a bit.


I noticed that too. My party hit level 2 before they got their loaner ship in the adventure path (which had a coil gun on a turret). I upgraded the ship, and threw a second coil gun on the turret and linked them. That 8d4 business was terrible for the enemy.

Dark Archive

SirShua wrote:
I noticed that too. My party hit level 2 before they got their loaner ship in the adventure path (which had a coil gun on a turret). I upgraded the ship, and threw a second coil gun on the turret and linked them. That 8d4 business was terrible for the enemy.

Oh man, yeah I imagine it would be. I mean that was a pretty one-sided fight to begin with.


Thanks mswbear, changing PCU would in my opinion not change that much. I don't think I can justify a PCU increase of more than 10 points and given the considerable amount of unused PCUs in the ship I don't think that would really decrease the superiority of the coilgun


I wouldn't change it. I imagine the coil gun is shooting Tungsten rounds or something. Just make them have to reload the gun every 4 rounds or something (as a full round action).


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Are full round actions even a thing in starship combat? And for that matter even in modern tech (like battleships) reloading artillery is frequently an automated system so one would imagine the computer would handle reloading.


Magabeus wrote:

After comparing the different light starship weapons it seems that the coilgun is too good to be true:

Coilgun Long range, average 10 damage (min: 4, max 16) per hit and costs 6 build points. 1.67 damage per BP

We can compare that to two other weapons that also have no special properties and have similar damage output:

Light particle beam Medium range, 10.5 damage (min: 3, max 18) for 10 BP: 1.05 damage per BP and shorter range.

Twinlinked light laser cannon Short range, 10 expected damage (min: 4, max 16) for a minimum of 8 BP: 1.25 (or less) damage per BP, shorter range and uses two mounts.

In my opinion these three options should be similar, with players really having to choose between the options. I would expect that with longer range comes lower damage output per BP. This is currently not the case.

Therefore I am seriously considering to increase the costs of coilguns to 10 BP. That would set their damage output per BP at 1.00, which is slightly lower than the light particle beam. The advantage of a coilgun is the longer range

You can take a look at the key figures here, I am curious to see what your thoughts are on the subject.

Edit: I should probably have posted this in homebrew or rules.

Your math is off. A full analysis requires some assumptions about the frame and the PCU, but you have to account for paying for the mounts when necessary, as well as the necessary PCU. I normally do my math assuming PCU is coming in at 10 per BP, because very few cores differ from that, and none of them are the most powerful for any given ship size. As you can see, Light Laser Cannons are more efficient than Coilguns initially, but as mount costs go up, the advantage disappears.

I modified your spreadsheet to pay for the BP cost of the PCUs consumed, assuming the standard rate, and included rows for twin-linked weapons where you had to pay for the second mount. I can add rows for both single and twin-linked where you have to pay for all mounts, if there is interest.

Silver Crusade

Magabeus wrote:
Thanks mswbear, changing PCU would in my opinion not change that much. I don't think I can justify a PCU increase of more than 10 points and given the considerable amount of unused PCUs in the ship I don't think that would really decrease the superiority of the coilgun

PCU tends to be fairly abundant but at a certain point you start trading hard for PCU and BP. One always falls short when there is still enough to do something with in the other (usually having extra PCU). You eventually start trading things for another....yes you have the ability to do more damage down range but you are easier to hit in return, your missile countermeasures are not that great, your shields are weak, speed suboptimal, sensors are mediocre, computer not giving you decent bonuses or more then one bonus each round.

That's why I think a bit of an increase in each PCU and BP is justifiable to some level.


I appreciate your reaction quindraco.

quindraco wrote:
Your math is off. A full analysis requires some assumptions about the frame and the PCU, but you have to account for paying for the mounts when necessary, as well as the necessary PCU.

I see no issues with my math. I think you do not agree with my assumptions, which we can discuss. It might also be that I did not explain my position enough.

The discussion was started because we were looking at outfitting a medium explorer with just the standard weapon mounts.
- I indeed ignore the fact that additional mounts for turrets are more expensive than for weapons that fire in a single arc. I have added a second version of the twinlinked laser for that, which is obviously worse than the current version because the additional weapon mount is more expensive.
- I compare like for like: all these weapons have a PCU consumption of 10
- It is my opinion that at this stage of the game BP are the limiting factor.
- The comparison is to determine what weapon is best for an available light weapon mount (and assuming that a second weapon mount can be installed)

I have added a column to account for PCU, using 10 PCU = 1 BP, which of course changes the denominator and therefore the comparison. However it does not change the result of the comparison: the coilgun is still far superior to a twinlinked light laser cannon and a light particle beam, before we take into account it's longer range.

My conclusion does not change for the situation at hand. Yes light lasers are more BP efficient, however they are far worse when it comes to actual combat because of action economy and the costs of additional weapon mounts. That is also the reason I did not include a single light laser in my opening post.

The nice thing about this limited comparison is that all three weapons (coilgun, twinlinked light laser and light particle beam) have rather similar damage output and the same PCU usage. If we ignore the small difference in damage profile between light particle beam and coilgun there are just a few variables that are different:
- BP cost
- Range
- Number of weapon mounts needed.

I simplify the comparison by assuming that there is no opportunity cost priced in for needing room for two weapon mounts for the twin-linked laser (I still pay for it).

It is my opinion that a shorter ranged weapon should not be worse than a longer ranged weapon. However the coilgun has a longer range and is superior to both a twin-linked laser and a light particle beam, where it should at best be equal to them.

I looked into fixing that by changing damage output, but that leads to similar issues that the light laser cannon is suffering from. Therefore I think that changing the BP cost to 10 is the way to go.


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Oh, yes, coilguns are incredibly good. Sorry if I came off as confrontational - I thought you'd missed stuff in your math. I didn't realize you had noticed, but had taken different assumptions.

I think the sanest way to balance them - taking the approach that we want these guns to be equivalent, sacrificing some things for others - requires quantifying how good range is. I would argue that medium range is twice as good as short, and long is twice as good as medium.

I have modified my linked spreadsheet, down at the bottom, to calculate damage-range for the stock weapons we're discussing, and then force the BP and PCU costs of the weapons that aren't light laser cannons to the same profile as light laser cannons - as you can see, plasma cannons and particle beams now cost less BP but more PCU, and Coilguns cost drastically more, to reflect how incredibly good they are. Obviously, you can make your own copy to fiddle with my math if you like.

Here's the cost dump for anyone who can't get the spreadsheet to load:

Weapon Name, BP Cost, PCU Cost
Light Laser Cannon, 2, 5
Coilgun (original), 16, 40
Light plasma cannon, 5, 15
Light particle beam, 8, 25


No problem quindraco. Your remarks forced me to put all of my thoughts on the web and not just the results.

I agree that the underlying assumption is that we want these guns to be roughly equivalent: sacrificing some things to gain something else.

I think that your solution to quantify range is the best solution, however that requires adjusting all weapons. I am not sure I want to go that route. Thanks for giving me food for thought.


Pathfinder Starfinder Roleplaying Game Subscriber
Shinigami02 wrote:
Are full round actions even a thing in starship combat?

They are not. Starship combat uses completely different time rules.


Keep in mind long range is NOT twice as good as medium range as there is not nearly so often a need for the extended range. As the factor of the value of the extra range is not the same as the factor of the difference between ranges one should have a smaller cost factor, closer to the factor of the value. So probably closer to 1.5, or even 1.25 between long and medium, and 1.75 to 1.5 between short and medium.

Sovereign Court

I think the difference between short and medium is much more significant than that between medium and long. When we were maneuvering to try to avoid the enemy's heavy front weaponry we often ended up very close to it. Often we managed to stay in short range, I think we almost never ended up beyond medium range.

Of course having longer range does help against opponents that don't have it. But it's not twice as good, occasionally it's "+2 to hit" good.


Pathfinder Starfinder Roleplaying Game Subscriber

It *can* be more than that. If the ship with long range weapons has equal or better speed to its opponent, it could try hanging out at, say, 40 hexes distance. This means they eat -4 to attack, but the opponent eats -8 if they have medium range weapons, or -16 if all they have is short range. Good set up for a prolonged "Hang back and blast the crap out of them" strategy, especially since most of your crew can focus on assisting the gunnery.


The Coilgun is an excellent "all-rounder" gun. It's cheap, not too power-hungry, has good range, and overall offers very good bang for its buck. Being D4-based it's also the most efficient weapon to combine with engineers that shunt power to weapons. All of this makes it very attractive for a low-tier ship.

Most medium/high tier ships are going to rely on Heavy guns if they can fit them (ie it's a medium ship or bigger, like an Explorer). If you're making a medium/high tier interceptor or fighter I'd consider using light plasma cannons or possibly chain cannons instead. Short range isn't ideal but it's not too bad as long as your superior mobility helps you dictate the engagement range, and the 40-50% damage improvement over coilguns is needed when you're going up against heavy weapons and stronger shields.


Yes, but coil guns are far and above the best light weapons, really making the others obsolete as soon as you can afford to replace them with coil guns. Honestly I think the easiest way to rebalance them would be to make their damage 3d4 instead of 4d4. This makes them good if you want long range, but makes particle beams better if you want damage.


I considered changing the damage when I did my initial calculations. That did not seem to change the ranking, however that was before I took into account 10 PCU as 1 BP. I added some changes to damage (3d4 / 2d6 / 1d12) to the sheet.

I think we will go that way, with either changing damage to 3d4 or 2d6.

Sovereign Court

I think 3d4 is the nicer choice because it makes the Divert Power To Weapons action more interesting. My experience as engineer so far is that raising shields is so compelling that the alternative actions need to get love too.


Would ship weapon range penalties apply? If so then you will have to apply zero-g's weapon use. You can use all ranged weapons to fire at any distance you just have to keep adding the max ranged nagative when and where it applies. The nagative continues to stack. Which reminds me of the mass effect 2 conversation detween the sergeant and his recruits when you first enter the Citadel.


It looks like a Breastplate situation (oh no! not again!) or a mere oversight (I hope).
An errata I would like would be to add a limitation to the coilgun:
* can fire every other round?
* cannot fire in the first range increment?

Same for the persistent particle gun.

Also, it feels like the starship weapon description section was just removed from the book. There's a lot of it (sometimes redundant) for weapons, why none at all for starships?


Yea the lack of descriptions, other than their special qualities, was kinda disappointing.


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This is a bit old, but my solution was to move CoilGun to short range.

The problem with changing cost is that I have to rebuild every npc ship and I'm not going to do that.

At short range it does the same damage than persistent particle beam, with less cost, but lower range. It also make heavy weapons the goto option for longer range, which I think it is good. It makes smaller and more mobile ships, like fighter, close combat ships, while bigger ships can shoot from afar.

Hope this help others.


Tried it yesterday with the houseruled Coilgun that can fire every other round. Was good. I allowed the engineer to Direct Power to the coilgun, allowing to fire every round.
So that kind of solved one of many starship combat issues...

I also nerfed shield regen to "its regen value (as per p. 302) on each side". Good thing, because the fight already dragged on enough to have allowed them to replenish their shields fully two times over.

Btw, Coilgun is bad. But the Particle Beam vs. Railgun is just crazy. I'm really confident now that they left off some special rule and forgot to redo the costs.

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