Foot outside of batters box

[Big Daddy Baker]

Scenerio:

FP. Slow rise ball. Batter goes after high, outside pitch and attempts to bunt. Places foot solidly down in front of homeplate (completely outside box) and then makes contact.

I rule batter out.

My philosophy has always been that is its close you give the doubt to the batter. As an example, slap hitters. etc.

Is this a call you shouldn't make?

Murray