Casting with a Weapon as a Spellcasting Focus...Do I still need War Caster?

I've been looking for the information on this and the answer isn't really clear.

New 2024 rules say that, for somatic components: "A spellcaster must use at least one of their hands to perform these movements." For material components, the same source says that a spellcasting focus or a component pouch can be used to replace any material components a spell may have. However, in an old Sage Advice using 2014 rules as a baseline, it says that: "If a spell has a somatic component, you can use the hand that performs the somatic component to also handle the material component."

This ties into my question. I have no idea what the ruling is for when a subclass/class, like Valor Bard or Artificer, is able to use a weapon as a spellcasting focus. Sources I have read on forums say that, RAW, you have to put the weapon away to cast a spell that has S components but not M. The Sage Advice says that you can use a hand you are using for S components to do M components. Why am I able to use the weapon in my hand as a focus for S and M spells, but not with just an S spell? Obviously, War Caster is a clear solution to this problem, but from a my standpoint, it doesn't make sense I would be able to perform S components with my weapon in my hand for a S&M spell and then magically not be able to for just an S spell.

I just need help with the clarification, because nothing is giving me a clear answer. Thanks!

Quote from Fenna >>

Sources I have read on forums say that, RAW, you have to put the weapon away to cast a spell that has S components but not M.

This is technically correct according to the official rules. When you're casting a spell that doesn't have an M component, you're not actually using the focus even if it's in your hand, so the bit about "you can use the hand that performs the somatic component to also handle the material component" doesn't apply, and the general rule of needing a free hand to do the somatic component applies. The fact that you can use a weapon as a focus doesn't change any of this.

However, many DMs — myself included — think this is incredibly stupid and nitpicky, and are happy to let players use a hand with a spellcasting focus in it to perform somatic components regardless of whether the spell has an M component. I don't think I've ever played with a DM who bothered to enforce this rule, and I've never enforced it myself.

What I'd suggest is that if you're the player in this situation, you check with your DM about how much they care about this before you make any decisions related to building your character that this issue might impact. And if you're the DM in this situation, unless you're really excited about the minutiae of spellcasting focus rules — which from the tone of your question I'm guessing you're not — I'd suggest you sweep the whole issue under the rug and just let people cast spells.

Okay, so it's technically correct RAW, then. I was just wondering. Thanks for the clarification.

I agree, it does seem very nitpicky and strange, that's why I was asking in general, just to see what other people thought. I was running a campaign with 2014 rules and I assumed that you could use S components for a spell without M components with a weapon casting focus for that entire time, so I was confused to see this rule just pop up out of thin air while I was looking around.

The DM in question is my buddy that was a player in said campaign, so I don't think he will enforce the weird rule. But yeah, for my campaigns, I'm gonna just let them cast the damn spells if they have a weapon focus. Again, thanks for the response. Sometimes getting a second opinion is what I need to validate the way I'm thinking about things :)

No problem!

And just for the record, the rule is the same in both the 5e/2014 and 5.5e/2024 rules. It's just not very well-known because it's kind of obscurely defined (it's less a rule on its own and more a consequence of multiple rules interacting) and because so many people don't bother with it.