SOURCE: Player’s Handbook

Rating the Benefits of Spell Sniper

Spell Sniper has three benefits:

Benefit #1 – 

-Double range of attack roll spells

Notably, this is not limited to ranged attack roll spells, but some cantrips that seem like they may benefit from this won’t benefit from it in practice: more on that later. Anyway, the doubled range is circumstantial but useful when the circumstances come up.

Benefit #2 – 

Ranged spell attacks ignore half and ¾ cover 

Cover usage varies from table to table. If your table treats lots of things as cover, then this will come up a lot. If enemies never happen to have any cover but full cover, this is useless.

Benefit #3 – 

Learn a cantrip from a class (except artificer), using that class’s spellcasting ability for it

You probably already have the best attack roll cantrips your class has to offer, and attack roll cantrips from a class using a different spellcasting ability than your good one will be weaker. Can still be useful, but rarely.

Mechanics and Requirements

Understanding How It Functions

First off, you need to be able to cast one spell to even take this feat (why you would take it if you couldn’t is inconceivable to me).

Doubling the range sounds simple, but it only applies when the range entry of the spell lists just distance, not if it says something like “Touch” or “Self (5 feet)”. This means you cannot extend the range of a Shocking Grasp or a Booming Blade. This does make some sense; after all, you’re a spell sniper, not an arm elongator.

Ignoring half and ¾ cover is also simple. If someone would get a bonus from these kinds of cover, they don’t benefit from it for your spell attacks. Note that shields and other AC bonuses are not considered cover, and you don’t ignore total cover. Notably, unlike the previous benefit, this doesn’t just apply to spells, but any spell attack, such as the Starry Form attacks of a Stars Druid.

Finally, being able to pick cantrips from other classes sounds good, but it’s not that good. In the best case scenario, you’re a sorcerer who takes the warlock’s Eldritch Blast, and without invocations, it’s just a fancy Firebolt with a better damage type and the option to spread out the damage.

Thorn Whip is also a good candidate if you somehow have a good wisdom score and don’t have access to the cantrip: perhaps you’re a cleric, but clerics don’t make tons of spell attacks anyway, and there are other ways to get Thorn Whip if your build really relies on it.

Key Stats

You need a high score in the ability you use for attack roll cantrips to make use of this: no sense ignoring cover if you just whiff all your shots anyway. If for some reason you want to take a cantrip with a different spellcasting ability than the one you have, it had better also be a high stat.

Ideal Characters for Spell Sniper

Top Classes

Warlock – Eldritch Blast, when enhanced with evocations, is the best cantrip by far. Therefore, taking Spell Sniper has two benefits: 1) you can snipe from ridiculous distances, especially with invocations, and 2) you can ignore cover and hit more often. The third benefit of Spell Sniper isn’t very useful for you though.

Cleric – If you have no other means of accessing it easily, you could take this feat solely to grab Thorn Whip and pull people into the area of your Spirit Guardians spell, making them take extra damage. Bonus points if you mix this with the Telekinetic feat for even more forced movement funnies.

Sorcerer – Only at low levels due to the lack of higher level attack spells. Do you cast Scorching Ray? Hate missing due to cover? Take this feat.

Multiclassing Considerations

Two levels of Warlock to make your Eldritch Blast actually good can make this feat much better. Notably, this feat is a substitute for clerics seeking to multiclass into Druid for Thorn Whip.

Race or Subrace Choices

Although some races give you attack roll spells, you were gonna pick attack roll spells anyway on a character who was good enough at using cantrips to take this feat, so those races aren’t worth mentioning.

The Bugbear from Monsters of the Multiverse is worth mentioning: if you combine the Eldritch Spear cantrip with this feat, you can snipe people from far away and add an extra 2d6 damage to each beam, which is rarely useful in dungeon crawling adventures but may be useful for assassination attempts; perch on your grassy knoll and blast the king from 600 feet away, then escape before the guards reach you.

Combos, Tactics, and Synergies

Complementary Feats

Although some feats can help boost spell attack roll damage somewhat like Elemental Adept, there aren’t any particularly handy synergies out there.

Spells that Synergize

Any attack roll spell benefits from this, but Eldritch Blast enhanced with evocations is the standout.

Strategies for Maximizing Spell Sniper Effectiveness

Be a literal sniper and/or be at a table that uses cover; that is how you make Spell Sniper good. If you gain Eldritch Blast and are level 5 or higher, remember that you can aim the rays at multiple targets: the nearly dead creature cowering behind a pillar might only need one of your shots to finish off, and you can use the other 1-3 shots for the boss.

Final Thoughts on Spell Sniper

Spell Sniper is not a powerhouse feat: it does not reward the strongest damage dealers, since a good crossbow expert/sharpshooter user will out damage any cantrip, even a buffed Eldritch Blast unless additional factors like Spirit Guardians or Spike Growth are involved.

However, for people who prefer to shoot spells and kill people, this is a decent pick for that playstyle.