Can you cast spells with a Somatic component if you're holding a two-handed weapon?

Question

I have a halfling cleric of Bahamut who wears his holy symbol as an amulet around his neck as a spellcasting focus (so material components are not an issue).
However, as per this question, this does not cover the Somatic component of any spells he casts.

He also wields a light crossbow as his only weapon, which has the two-handed weapon property.
How does RAW handle Somatic casting when you're holding a two-handed weapon? Can I simply take a hand off my weapon, cast the spell, and re-grip all in the same action?
If not, has anyone run into this problem at their table before and how did you handle it?

Answer 1

Taking your hand off the weapon should not require any action expenditure - you are just letting go of it, same as if you dropped it.

You can then use your free object interaction to restore your grip after casting.

The PHB Errata says:

Two-Handed (p. 147). This property is relevant only when you attack with the weapon, not when you simply hold it.

So you can hold it with one hand while you are not attacking with it.

Answer 2

The two handed weapon property reads:

Two-Handed. This weapon requires two hands to use.

It says nothing about requiring 2 hands to hold, carry, or lift.

The heaviest weapon in the game is the Pike, or the Heavy Crossbow, at 18 lb. However, the amount you can lift is your Strength score multiplied by 30. Even assuming that lifting with one hand only allows you to lift half your normal capacity, a character with a Strength score of 8 (the lowest score possible with stat arrays or point buy) can lift 120 lb with 1 hand. So an 18 lb weapon should present no difficulty whatsoever.

As for the difficulty of gesturing with one hand while holding something in your other hand, every character can do that anyway, so there's no reason it would present a difficulty.

Now, for action economy: You have one free object interaction per turn. So you can take a hand off your weapon and cast a spell in one turn, then next turn you can put your hand back on your weapon to attack. Note that the Ammunition property works as part of the attack, so it doesn't need your free object interaction. Note that this leaves you unable to attack between your turns, but the only reaction you commonly take with a weapon is an opportunity attack, and you can't do that with a ranged weapon. Of course, you would be unable to take the reaction from a Commander's Strike maneuver (for example).

Answer 3

Let's look at it this way; an archer can, as part of their attack action do the following, while maintaining a grip on their two-handed bow with one hand:

1. Reach to their quiver
2. Draw an arrow Align the nock with the string
3. Put the nock on the string
4. Change their grip on the arrow/string
5. Draw the string back Release the string

Here we have gripping and ungripping of a weapon with one hand, while manipulating an object with that hand, and it is completely incidental to the use of said weapon. At higher levels, the archer can repeat this process multiple times during the same action.

To argue that a wizard can't:

1. Release their versatile staff with one hand,
2. Make a gesture with their free hand,
3. Return their hand to their staff

Here we have the gripping and ungripping of a weapon with one hand, without manipulating an object with that hand, but the argument is being made that it takes some form of action to do this?

That's a pretty hard argument to make. Both are grabbing/releasing the weapon with one hand the same number of times. The archer additionally has to manipulate an object with their other hand. (That's fine motor control in a high-stress, combat situation.)

If the archer can manage it, the wizard certainly can.

Additionally, interpreting the requirements of a Somatic component that way would make it impossible for a wizard to cast a spell with both Somatic and Material components without spending the prior round 'drawing' the spell component(s) and freeing a hand to make the gesture.

Answer 4

This feat settles it fairly clearly in my opinion.

WarCaster

Prerequisite: The ability to cast at least one spell You have practiced casting spells in the midst of combat, learning techniques that grant you the following benefits:

• You have advantage on Constitution saving throws that you make to maintain your concentration on a spell when you take damage.
• You can perform the somatic components of spells even when you have weapons or a shield in one or both hands.
• When a hostile creature’s movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature.

This feat, from 5th edition, states "You can perform the somatic components of spells even when you have weapons or a shield in one or both hands.", implying that without this feat you would be unable to perform somatic spells with these things in your hands.

Essentially, if you're not holding a focus item, you need a completely free hand. This makes sense as every casting archetype has a focus of some sort intended for use in combat. The Eldritch Knight and other classes that take auxiliary spells must either run around with one hand empty, or take this feat if they plan on casting somatic or material based spells in combat.

Answer 5

Not a RAW, but quote from designer's twitter

Matt Petruzzelli ‏@mpetruzz Jul 28

Does an arcane focus staff also/always count as a quarterstaff? @mikemearls

Mike Mearls ‏@mikemearls

@mpetruzz believe so, yes. i think that's why the quarterstaff became a one-handed/versatile weapon

Whilst not a proof, it is at least strong indication that temporarily holding a two handed weapon with one hand to cast a spell was not meant to be possible, by design. Of course RAW sometimes differs from intentions, and I admit I can't find strictly logical indication of this in rules.

RAI

As far as I understand RAW, you can hold it one handed, sure, but you can only draw or sheath for free in round. And the only RAW option to get hand free from weapon, other than sheathing that weapon, is to drop on the ground if I recall correctly. So taking a hand off the crossbow would have to be considered a kind of sheathing, making PC considered unarmed and unable to use that crossbow until the beginning of his next turn when he can "officially" draw it with hand he used for spellcasting. Pretty consistent with first section, I'm afraid.

Personally

I see no reason what you described should not work. Your character obviously can hold that crossbow with one hand when he uses other hand to pull next bolt from quiver, and no actions or interactions are considered spent, are they? Don't see why doing the same to get a hand for spellcasting should be that different. But I admit, I would treat this as a houserule.

Answer 6

There could be an easy answer to this problem, if we take a look at the booming blade cantrip. It requires somatic and material components. The material component is provided by the melee weapon carried and the somatic component needs one free hand.

RAI + RAW -> No need for a workaround to cast this spell (this cantrip) while 1. holding a weapon, 2. casting and 3. attacking in one action. The intended action economy allows for all of this in one action (and still leaves your bonus action for something else that round).

Because holding a two-handed weapon in one hand is possible (while not attacking), it is possible to cast a spell with somatic components while doing so. Take a halberd for example, that also has the "heavy" property. Simply put the shaft on the ground and you have one free hand. All other two-handed weapons, like a sword, can also be hold in multiple ways using one hand. The same is true for ranged weapons.

Ranged weapons: A bow actually is an one-handed weapon that just needs another hand to load it (during the attack action). Leaving your free hand to cast a spell.

I have to say, that the warcaster feat can be kind of confusing here. Yes it states that you "can perform the somatic components of spells even when you have weapons or a shield in one hand or both hands". BUT if this is to be read as restrictive as one previous post did, than you would need this feat to cast booming blade. And this clearly isn't the case. Warcaster makes it possible, to hold a shield and a weapon (or two weapons) while still being able to cast a spell.

Answer 7

Two handed weapons only require the two hands when attacking as previously mentioned, meaning that you can let go with one hand during casting. If that weapon forms part of the material cost (eg the Improved Pact Weapon feat) then you can use your free hand to do the somatic cost of the spell. However, if the weapon doesn't meet that cost you would either have to have the Warcaster Feat (which states that you can perform that cost regardless if your hands are full) or drop the weapon to fulfill the somatic and material cost of many spells.