Is it possible to use Sneak Attack with the Magic Stone cantrip?

Question

The description of the rogue's Sneak Attack feature says:

Once per turn, you can deal an extra 1d6 damage to one creature you hit with an attack if you have advantage on the attack roll. The attack must use a finesse or a ranged weapon.

The description of the Magic Stone cantrip says:

You touch one to three pebbles and imbue them with magic. You or someone else can make a ranged spell attack with one of the pebbles by throwing it or hurling it with a sling.

The attack is a ranged spell attack (not a weapon attack), but if I use a sling, I am using a "ranged weapon". By RAW does this make it possible to add the Sneak Attack damage or not?

Answer 1

Yes. You can sneak attack with any ranged weapon.

Throwing by hand, no. A pebble is not a finesse or ranged weapon.

Hurling with a sling, yes. See Sneak Attack in the PHB:

Sneak Attack (PHB p.96, emphasis mine)

Beginning at 1st level, you know how to strike subtly and exploit a foe’s distraction. Once per turn, you can deal an extra 1d6 damage to one creature you hit with an attack if you have advantage on the attack roll. The attack must use a finesse or a ranged weapon. You don’t need advantage on the attack roll if another enemy of the target is within 5 feet of it, that enemy isn’t incapacitated, and you don’t have disadvantage on the attack roll. The amount of the extra damage increases as you gain levels in this class, as shown in the Sneak Attack column of the Rogue table.

Sneak Attack considers the weapon properties not the attack type. While not using the usual modifies, as per spell description, you are hurling a stone with a ranged weapon.

Since you normally can apply Sneak Attack to a sling shot, why should using an enhanced projectile be worse than that?

A rogue cannot access the Magic Stone cantrip inexpensively, so I'd consider this clever synergy.
Also the resulting damage isn't imbalanced.

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The unofficial ruling by Jeremy Crawford is also a yes.

As DM, I'd allow it to work, given how Sneak Attack and magic stone are worded.

Answer 2

"The attack must use... a ranged weapon" is not synonymous with "The attack must be a ranged weapon attack". A sling is a ranged weapon; ergo, an attack that "uses a sling" is an attack that "uses a ranged weapon", no matter whether that attack is a "ranged weapon attack" or a "ranged spell attack".

If you ponder whether ammunition is a ranged weapon, then you would also have to conclude that you can't sneak attack with mundane bows either since the arrow isn't a ranged weapon; this is obviously nonsensical but irrelevant since the attack "uses" the sling regardless.

Answer 3

Sneak Attack can be used when using a sling to hurl a Magic Stone

However, it cannot be used when just throwing the stone.

Sneak Attack has 3 requirements to be met to activate

Sneak Attack (PHB 96)

Beginning at 1st level, you know how to strike subtly and exploit a foe’s distraction. Once per turn, you can deal an extra 1d6 damage to one creature you hit with an attack if you have advantage on the attack roll. The attack must use a finesse or a ranged weapon. [...]

1. Hit with an attack

The Magic Stone cantrip states

make a ranged spell attack with one of the pebbles by throwing it or hurling it with a sling

So what counts as an attack?

Making an attack (PHB 194)

If there's ever any question whether something you're doing counts as an attack, the rule is simple: if you're making an attack roll, you're making an attack.

Since a ranged spell attack uses an attack roll (PHB 205, Attack Rolls), then unsurprisingly it counts as an attack.

2. Must have advantage on the attack roll (or other conditions)

This requirement is circumstantial, but advantage (or other conditions) are not prevented by the use of either a sling, nor by throwing the stone, nor by the attack being a ranged spell attack, so this condition is not being contested here.

3. The attack must use a finesse or a ranged weapon

Again, the Magic Stone cantrip states

make a ranged spell attack with one of the pebbles by throwing it or hurling it with a sling

A sling is listed under the simple ranged weapons (PHB 149), and it is explicitly stated that the attack is being made by hurling it with the sling, so that checks out.

Throwing the pebble does not use a ranged weapon, so it does not qualify for Sneak Attack damage, due to this condition.

Summary

Based on the above requirements, hurling a Magic Stone enhanced pebble with a sling qualifies for Sneak Attack. If the pebble is thrown without use of a sling, it does not qualify.

Note that the wording of Sneak Attack does not require a ranged weapon attack, as attacking with a ranged weapon and making a ranged weapon attack are distinct and separate things.

Trivia

Apparently during the playtest phase the original rules for Sneak Attack did not require a finesse or ranged weapon. As a result, any spell with an attack roll met the requirement for Sneak Attack, which is likely why they added that restriction.

Whether or not all spells were intended to be excluded is unknown, but by RAW (as outlined above), Magic Stone still qualifies.

Answer 4

No

To Sneak need Weapon
Magic Stone gives Spell Attack
So no Sneak with Stone

Answer 5

Yes, most definitely all improvised weapons can be ranged. To understand why I say that, read on:

First as Jeremy Crawford points out: http://www.sageadvice.eu/2015/11/12/magic-stone-sneak-attack/

Attacking magic stone with a sling is just a spell attack with a sling. (Corollary, using it by hand is just a spell attack with an improvised weapon).

First the rules of sneak attack:

Beginning at 1st level, you know how to strike subtly and exploit a foe’s distraction. Once per turn, you can deal an extra 1d6 damage to one creature you hit with an attack if you have advantage on the attack roll. The attack must use a finesse or a ranged weapon. You don’t need advantage on the attack roll if another enemy of the target is within 5 feet of it, that enemy isn’t incapacitated, and you don’t have disadvantage on the attack roll. The amount of the extra damage increases as you gain levels in this class, as shown in the Sneak Attack column of the Rogue table.

Now, the rules on improvised weapons:

If a character uses a ranged weapon to make a melee attack, or throws a melee weapon that does not have the thrown property, it also deals 1d4 damage. An improvised thrown weapon has a normal range of 20 feet and a long range of 60 feet.

Now lets examine the thrown property. (True the wording of previous doesn't technically grant 'thrown' but for additional support.

Thrown. If a weapon has the thrown property, you can throw the weapon to make a ranged attack.

Next lets look at the definition of ranged weapon within the PHB

Every weapon is classified as either melee or ranged. A melee weapon is used to attack a target within 5 feet of you, whereas a ranged weapon is used to attack a target at a distance.

Since the stone is improvised it gains an attack range of 20/60 per the rules of improvised. Per the rules on what determines what a ranged weapon is "is used to attack a target at a distance" the pebble is a ranged weapon.

Additionally, lets examine the definition of "Range".

Range. A weapon that can be used to make a ranged attack has a range in parentheses after the ammunition or thrown property. The range lists two numbers. The first is the weapon's normal range in feet, and the second indicates the weapon's long range. When attacking a target beyond normal range, you have disadvantage on the attack roll. You can't attack a target beyond the weapon's long range.

Since the rules of improvised weapons provide the weapon a range increment, it confirms that the stone without a sling is still considered a ranged weapon.

Put very specifically, by RAW anything can be turned into a 'ranged' weapon. Even a dead cat. Applying magic stone to the pebble doesn't change the fact that it is already considered a ranged weapon. The only thing that changes is that it becomes a spell attack with a ranged weapon versus a standard ranged attack with ranged weapon.

On that note, lets examine the Booming Blade cantrip.

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects, and it becomes sheathed in booming energy until the start of your next turn. If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends.

This is a spell that requires a melee attack roll. Could someone using this spell not benefit from sneak attack on the original attack roll just because they are utilizing a spell? The answer is no, of course they could use sneak attack assuming the weapon was a finesse weapon or had advantage. The fact that they utilized a weapon, and made an attack roll to utilize the spell effect are all that's important.

The same can also be said for steel wind strike (yet your capped at one target of sneak attack per turn, require advantage and finesse). I.E. It's a melee attack that uses a spell attack roll instead.

You flourish the weapon used in the casting and then vanish to strike like the wind. Choose up to five creatures you can see within range. Make a melee spell attack against each target. On a hit, a target takes 6d10 force damage.

You can then teleport to an unoccupied space you can see within 5 feet of one of the targets you hit or missed.