Concentrated Fire

Concentrated Fire is a perk in Fallout 3, Fallout: New Vegas, Fallout 4, Fallout 76, and the Fallout: The Board Game add-on Fallout: New California.

Fallout 3 and Fallout: New Vegas
Each successive time you target the same body part in V.A.T.S., your chance-to-hit raises by +5%. So, if your first to-hit was 40%, 2nd would be 45%, 50%, etc. This can lead to very easy head-shots when teamed with other to-hit % boosters (Sniper, Commando, etc.)

Fallout: New California
Concentration Fire is added to the game with the Fallout: New California. While in a fight, the player character can discard the perk card in order to change two of the VATS dice to match the third die of their choice.

Bugs
In Fallout 4, the second rank of this perk does not work, although the first and third ranks do.
 * This is caused by the second rank incorrectly affecting the V.A.T.S. damage by 15% similar to rank 3 of the perk.

Gallery
Massiertes Feuer Fuego concentrado Tir Groupé Skoncentrowany ostrzał Массированный огонь Масований вогонь