Setting histogram bar width

I use the following code to create a histogram, and set the properties, but the bar widths do not stay consistent. Any ideas why?

[n,x]=hist(data{1,j}{1,5});
h(j)=bar(x,n,'BarWidth',.05,'FaceColor',color_prop(j,:),'EdgeColor',color_prop(j,:));

I do this for multiple data sets (using j in a loop).