Cannons! How much should they cost and other questions.

[SkipSandwich]

So in the DMG there is a section on siege weapons with an entry for a cannon. there is no listed price for this weapon, and generally the difficulties of transporting it alone would preclude using it on a regular basis, but just funsies i'd like some help at least getting a good ball-park estimate of the cost in case I ever get some pc's who want to incorporate them into the design of a stronghold or pirate ship or something.

On a related note, most siege weapons require separate actions to Load, Aim and Fire, respectively, as such benefit from a crew of multiple creatures to keep them firing once per round. But what about a Rogue (Thief sub-class) with the Fast Hands feature, can they use their bonus "Use an Object" action to Load, Aim or Fire? What about a Fighter with Extra Attack(2), could they use their three attack actions to man a cannon by themselves?

[Potato_Priest]

Rogue could use their fast hands bonus action for of those actions, yes.

The fighter could not without a houserule.

[Talamare]

I would make the cost based on how much you're granting your PCs

It should be high enough to be restrictive.

I would say probably 500-5000g for the Cannon itself, Depending on the size.

Another 50g for the Gunpowder and associated items needed to fire the cannon. 250g for 5 shots.

Finally, another 10-40g for the ball. Depending on the size.


I would also play it that it's 1 Action to Load it, 1 Action to Aim it, and 1 Action to Fire it.
A Rogue could use the Fast Hands to Fire it, but cannot use Fast Hands to Aim it nor Load it.

Edit
I just did a bit of research on the subject.
I would actually play it as 1 Action to Load the Gunpowder, 1 Action to Load the Ball, 1 Action to Aim it, 1 Action to Fire it, 1 Action to Clean it.
You may not Reload it in the same turn that you're Cleaning it.

This would align it roughly with the average fire rate of a Real Cannon, and why you would want multiple people assisting it.
I would also restrict Rogue's Fast Hands to being able to Load the Gunpowder and Firing it.

Ancient Gunpowder is also insanely expensive since it was insanely difficult to manufacture. There were very few natural sources of it.

[JackPhoenix]

Rogue sounds fine.

Fighter do *not* get three attack actions, he gets multiple attack with single attack actions, there's a difference. He can use Action Surge, though, that one grants extra action.

Fighter 2/Rogue (thief) 3 can use regular action to reload, Cunning Action to aim, and then use Action Surge to get extra action to fire. All in a single turn, but it uses limited resource.

[napoleon_in_rag]

Finally, another 20-100g for the ball. Depending on the size.



What's the ball made out of, gold? It's a cast iron sphere. Shouldn't cost any more than an equal weight of iron ore.

[Rusvul]

Gold in 5e is kind of meaningless BS. There's not really any rhyme or reason as to why things are priced the way they are, as far as I can tell. Cannons should be moderately expensive, cannonballs should be fairly cheap, gunpowder should probably be affordable but not cheap. Since 5e doesn't really give us the tools to determine prices based on in-universe logic, I would recommend pricing your cannons based on how many cannons you want to have around. If cannons are cheap, they'll be widely used. If they're expensive, you'll see mostly ballistae and onagers and the like when small siege weapons are called for, with cannons used only sparingly.

[JackPhoenix]

Gold in 5e is kind of meaningless BS. There's not really any rhyme or reason as to why things are priced the way they are, as far as I can tell. Cannons should be moderately expensive, cannonballs should be fairly cheap, gunpowder should probably be affordable but not cheap. Since 5e doesn't really give us the tools to determine prices based on in-universe logic, I would recommend pricing your cannons based on how many cannons you want to have around. If cannons are cheap, they'll be widely used. If they're expensive, you'll see mostly ballistae and onagers and the like when small siege weapons are called for, with cannons used only sparingly.

We've got canon (heh) prices for gunpowder: 250 gp per 20 lb keg, 35 gp per 2 lb horn, but no idea how much of the weigth is the container itself. Pistol is 250 gp, musket is 500 gp, no price for cannon. Also 3 gp for 10 bullets.

[Talamare]

What's the ball made out of, gold? It's a cast iron sphere. Shouldn't cost any more than an equal weight of iron ore.

Fair, I reduced the price in that post to 10-40g

[No brains]

I wonder if someone with Crossbow Expert could get away with loading a ballista quicker because they ignore the loading property of crossbows. If the DM previously had a 'Pistol Expert' equivalent, I wonder if that could translate to cannons. Just imagine a Thief Rogue blasting off siege weapons each round with fast hands and dubious cheese.

[SkipSandwich]

Thanks for all the feedback!

I figured the Rogue's bonus action would work just fine by RAW, but it's also good to have the clarification on exactly how Extra Attack works as well.

Regarding cannon size, the default one in the DMG is a Large sized object and deals 8d10 damage on a hit and requires three separate actions to load, aim and fire.

How would a down-scaled balista (arbalest) or cannon (hand cannon) work?

It would have to have a trait like Slow Loading: This weapon requires a separate action to load before it may be fired. A friendly creature standing within 5ft may spend their action to load the weapon on your behalf on their turn.

Arbalest: Martial ranged weapon, Ammunition, Slow Loading, Two-Handed, Heavy. Damage 2d10 Piercing (compare to heavy crossbow).

Hand Cannon: Martial ranged weapon, Ammunition, Slow Loading, Two-Handed, Heavy. Damage 2d12 (compare to musket).

Thoughts?

[Potato_Priest]

Thanks for all the feedback!

I figured the Rogue's bonus action would work just fine by RAW, but it's also good to have the clarification on exactly how Extra Attack works as well.

Regarding cannon size, the default one in the DMG is a Large sized object and deals 8d10 damage on a hit and requires three separate actions to load, aim and fire.

How would a down-scaled balista (arbalest) or cannon (hand cannon) work?

It would have to have a trait like Slow Loading: This weapon requires a separate action to load before it may be fired. A friendly creature standing within 5ft may spend their action to load the weapon on your behalf on their turn.

Arbalest: Martial ranged weapon, Ammunition, Slow Loading, Two-Handed, Heavy. Damage 2d10 Piercing (compare to heavy crossbow).

Hand Cannon: Martial ranged weapon, Ammunition, Slow Loading, Two-Handed, Heavy. Damage 2d12 (compare to musket).

Thoughts?

If you're a fast hands rogue it's great. If you aren't and don't have someone to back you up with the loading (like a familiar or unseen servant) you're better off with a regular version of the weapon, since you'd get to apply your ability score modifier to damage more frequently while getting the same dice.

With weapons like this you run into an interesting conundrum: A player is rewarded for carrying 3-5 of these weapons loaded at any one time and then firing and dropping them one by one. Because the enemy would need an action to reload them, they don't even need to worry too much about the enemies picking their weapons up to use against them.

[SkipSandwich]

If you're a fast hands rogue it's great. If you aren't and don't have someone to back you up with the loading (like a familiar or unseen servant) you're better off with a regular version of the weapon, since you'd get to apply your ability score modifier to damage more frequently while getting the same dice.

With weapons like this you run into an interesting conundrum: A player is rewarded for carrying 3-5 of these weapons loaded at any one time and then firing and dropping them one by one. Because the enemy would need an action to reload them, they don't even need to worry too much about the enemies picking their weapons up to use against them.

There is some room for cheese, true, but I don't really see that as a downside so much since its designed to be like the larger siege weapons themselves, something inherently more practical in the hands of the DM, but which a player could conceivably make use of under the right circumstances and with clever planning, without having to resort to DM Handwave since both PC and DM would be working under the same rules.

While thinking about this, I came up with a summarized weapon property that could be used to design custom siege weaponry.

Crew-Served (X). This weapon is a Large (or larger!) object that occupies its own space on the battlefield. It requires separate actions to Load, Aim and Fire, which may be taken by any creature within 5ft of the weapon that is proficient in its use. The number of actions required to Load or Aim is based on the weapon's size, Large weapons require one action each, Huge weapons require two actions, and Gargantuan weapons require four actions. Firing a Crew-served weapon takes only a single action regardless of size. When Aiming a Crew-served weapon, you designate a single area equal to the weapon's size. When firing, the weapon targets all creatures in the aimed at square(s) and makes a single attack roll for each. When summarizing the weapon properties, the number of actions required to Load and Aim is listed in parenthesis.

Large Cannon: Ranged Siege Weapon, Ammunition, Crew-Served (1), Damage 8d12 Bludgeoning Range 600ft/2,400ft Target 1 10ft Square

Huge Cannon: Ranged Siege Weapon, Ammunition, Crew-Served (2), Damage 16d12 Bludgeoning, Range 800ft/3,200ft, Target 1 15ft Square.

"Dragonsbane" Gargantuan Cannon: Ranged Siege Weapon, Ammunition, Crew-Served (4), Damage 32d12 Bludgeoning, Range 1,000ft/4,000ft, Target 1 20ft Square

[MrStabby]

I class siege weapons as land vehicles. Proficiency with land vehicles is otherwise pretty useless and it seems that proficiency with a cannon needs a really difference skill set to proficiency with a greatsword so it wouldn't come under normal weapon proficiency.

[SkipSandwich]

@MrStabby

Totally with you on that, though to me it would make more sense to have a separate Siege Weapon proficiency then to bundle it up with Vehicles (Land). Sorry vehicle proficiency, but don't think you'll see much use until some enterprising player thinks to make a battlewagon.

:EDIT: I felt so bad for the poor, neglected Land Vehicle proficency skill, I made a battlewagon!

Battlewagon - This oversized wagon is designed to be drawn by two draft horses working in tandem, and measures 10ft wide by 15ft long and weighs approximately 2,000lbs when empty. The wagon itself is reinforced with thick wood and iron banding, giving it 50 hit points and an AC of 17. It has room for one driver in the front and up to six medium sized creatures in the wagon bed itself. The high sides of the wagon give any medium sized creature within one-half cover against ranged attacks coming from the front, sides or back of the wagon while standing (small creatures receive three-quarters cover instead). The wagon itself is armed with two Swivel Guns (see below) designed to be used from inside the wagon bed (one on each side, near the front corners). The total cost of the vehicle is 7,000gp
Varient: for those not using gunpowder weapons, the weapons can be removed, this reduces the price down to 3,000gp.

Swivel Gun: Medium Siege Weapon, Ammunition, Slow-Loading, Range 100ft/400ft Damage 4d12 Bludgeoning Target 1 5ft square, Cost 2,000gp, Weight 100lb (with firing stand, gun alone 50lb).