Iron Grip

With Iron Grip, 100 Strength grants 50% increased Projectile Attack damage through the Keystone but no longer grants Strength's inherent 200 maximum Life. The damage applies only to Projectile Attacks, not every Projectile and not every Attack. Iron Grip currently comes from Irongrasp rather than the passive tree, and the same body armour also grants Iron Will.

Strength no longer grants its inherent Life

The line Gain no inherent bonus from Strength removes Strength's ordinary +2 maximum Life per point. Other explicit bonuses that happen to scale with Strength are separate and follow their own wording.

Two Strength grants 1% increased damage

The Keystone grants 1% increased Projectile Attack damage per 2 Strength. At 100 Strength the resulting modifier is 50% increased Projectile Attack damage.

Both Projectile and Attack must match

The modifier requires a damage component to belong to a Projectile Attack. A Projectile Spell is not an Attack, and a non-Projectile Attack does not satisfy the Projectile scope.

The damage is Increased

The Strength-derived value joins the applicable Increased and Reduced Projectile Attack damage pool. It is not a separate More multiplier.

It is not on the current passive tree

Iron Grip is a valid current Keystone effect, but the official 0.5.2 passive tree contains no Iron Grip node. Irongrasp grants the effect directly.