D3 chart does not extend to full svg width

I have a histogram ( http://tributary.io/inlet/4720197 ) that displays a dataset with a lot of points that I cannot get fill the full width of the svg. I had the same problem with a line chart and was able to resolve it using rangePoints.

I'm trying something similar with this chart, but can't get the right combination (it uses two scales for grouping) and it's not clear how to get the side-by-side bars that I previously did with rangeBand () if this function doesn't exist using ranges. What am I missing?