Requirements: Level 18, Small Guns 60, Energy Weapons 60
Benefit: With Concentrated Fire, your accuracy to hit any body part in V.A.T.S. increases slightly with each subsequent hit on that body part.
 New Vegas
Because Concentrated Fire increases accuracy by 5% for every subsequent hit on a body part, it is considered more useful for players focussing on rapid fire weapons that require very few Action Points.
Snipers and heavy weapons players who rely on V.A.T.S should not bother with this perk.