I think you see the answer to your question when looking at the chain around the nose sprocket. The pintail acts like a safety bumper when the cutter rotates the nose making kickback less of an issue. What I like about the design is the fact the pintail only sticks out when it rotates the nose, when it runs down the bar it is hidden behind the cutter not interfering with performance. Its a well thought out design for sure. MAC were on the ball in their heyday! Its the same with those 'tailed' drive links, they too only function when the chain goes around the nose....clever.