ChartGroup.BinsType (PowerPoint)

Specifies how the horizontal axis of the histogram chart is formatted, by bins type.

Possible Values are xlBinsTypeAutomatic - Sets bins type automatically, xlBinsTypeBinCount - Sets bins type by count, xlBinsTypeBinSize - Sets bins type by size, xlBinsTypeCategorical - Sets bins type by category, xlBinsTypeManual - Sets bins type manually.
ActiveWindow.RangeFromPoint.Chart.ChartGroups(1).BinsType = xlBinsTypeAutomatic