Marksman's Luck

Martial Feat (Prerequisite: Level 4+, Proficiency in a ranged weapon)

You gain the following benefits:

+1 to your Dexterity score, to a maximum of 20.

Once per turn, when you roll for damage with a ranged weapon, you can flip one of the damage dice over and use the number on the bottom. You can’t use this ability on d4s. Note that for a balanced die, the top and bottom numbers add up to one more than the die’s largest number.