The invention provides a crusher block assembly for a particulate size reduction system including a crusher block having an inboard face configured and adapted to cooperate with a swing hammer in a crusher chamber of a particulate size reduction system to crush particulate, and an outboard face for receiving an adjustment mechanism. The crusher block assembly also includes an adjustment mechanism joined to the outboard face on the crusher block. The adjustment mechanism is configured and adapted to adjust the position of the crusher block along a direction between an inboard location and an outboard location within the crusher chamber. The invention also provides a method of adjusting clearance between a swing hammer and a crusher block in a particulate size reduction system.