Usually buckshot patterns out of a given barrel at a given range run smaller than birdshot patterns do. Getting 'fringed' with birdshot might well mean a clean miss with buckshot at the same range.
One lesson to take away from this IMHO is that you CAN miss with a shotgun, especially at close range.
Mindset - Skillset - Toolset. In that order!
Attitude and skill will get you through times of no gear, better than gear will get you through times of no attitude and no skill.