Three barrel versus four barrel hitting

[12 piece bucket]

12PB

In both a triple and four-barrel hitter's action, the right shoulder must actively move downplane and in both the right shoulder has to be the launching pad for release of PA#1. So, what's the key (definitional) difference between a triple barrel hitting action and a four-barrel hitting action?

Jeff.

The pivot loads the #4 pressure point . . . .