To print narrow barcodes with DevExpress, do the following:

– create your report

– add a XrBarcode report control to the report and configure it (bind it to fields,  choose symbology, configure symbology)

At this point, if you try to have a small width for the field, it is very likely the control will print an error text like ‘control bounds’.

Do the following:

– verify the symbology (for example, if using code 128 and displaying only digits, use Charset C)

– set the report measuring units to TenthsOfAMillimeter

– set the XrBarcode Modulo value to 2; if you try to make it smaller, the barcode will not be readable.

A code sample can be found on SkyDrive