A bikini-type gauge plate with multiple holes covered by foil was used in a side-on geometry to investigate blast features close to a powder-filled line charge on ground. It was found that the blast effect recorded by the gauge could be better associated with positive impulse than with peak overpressure, based on published values of measured and calculated shock parameters of the blast from linear charges. An explanation for the low values of blast effect with the line on dry sand is given. Aluminium and APC powders as additives to the powder fill cause a significant increase in blast effect overall, and is even more beneficial in the dip region. The cause of the general absence of a dip in positive impulse and the existence of patches with low blast effect from multi-strand linear charges has been deduced. One should use square-root Hopkinson blast scaling for line charges.