Your prowess with a specific simple weapon is beyond compare.
Benefit(s): Select one simple weapon you are proficient with. When making additional attacks as a result of a high base attack bonus, each attack after the first has its attack bonus reduced by 4, rather than by 5. This does not change the number of additional attacks you gain, only the attack bonus used by each additional attack.
For example, Thorne is a 19th level cleric proficient with the morningstar who has taken Mythic Simple Weapon Proficiency with that weapon. Normally she would receive three attacks as a result of her base attack bonus, at +14/+9/+4. However as a result of this feat, her three attacks are instead at +14/+10/+6.
Mythic Options: The Missing Core Feats. © 2013, Owen K.C. Stephens; Author: Owen K.C. Stephens