Add or remove margins from a paginated report chart (Report Builder)
Applies to: 
Microsoft Report Builder (SSRS)
Power BI Report Builder
Report Designer in SQL Server Data Tools
For Column and Scatter chart types in paginated reports, the chart automatically adds side margins on the ends of the x-axis. In Bar chart types, the chart automatically adds side margins on the ends of the y-axis. In all other chart types, the chart doesn't add side margins. You can't change the size of the margin.
This article doesn't apply to pie, doughnut, funnel, or pyramid chart types.
Note
You can create and modify paginated report definition (.rdl) files in Microsoft Report Builder, Power BI Report Builder, and in Report Designer in SQL Server Data Tools.
Enable or disable side margins
Right-click the axis and select Axis Properties. The Vertical or HorizontalAxis Properties dialog appears.
On the Axis Options page, set the Side margins property:
Auto: The chart determines whether to add a side margin based on the chart type.
Disabled: Bar, column, and scatter charts have no side margins.
Select OK.