Since World War I, helmets have been used to protect the head in warfare. They have been designed primarily for protection against artillery shrapnel. More recently, helmet requirements have included ballistic and blunt trauma protection, but neurotrauma from primary blast has not been a key concern in helmet design. This study compares the blast protective effect of historical (WWI) and current combat helmets, against each other and the ‘no helmet’ case, for realistic shock wave impingement on the helmet crown. Helmets included WWI helmets from the UK/US(Brodie), France (Adrian), Germany (Stahlhelm), and a current US combat helmet (ACH). Helmets were mounted on a Hybrid III® (Humanetics) dummy head and neck and faced towards the ground with a cylindrical blast tube (30.5 cm diameter) aligned along the crown of the head to simulate an overhead blast. Primary blast waves of different magnitudes were generated. Peak reflected overpressure at the open end of the blast tube was compared to peak reflected overpressure at the crown of the head. A general linear model was used to assess the effect of helmet type and tube pressure on the resultant crown pressure response. The interaction between helmet type and tube pressure was found to have a significant effect on the outcome. ‘No helmet’ and the Adrian helmet were each found to be statistically significantly different from all other helmets. The peak crown pressure was lowest in the Adrian helmet and highest in the ‘no helmet’ case. The Stahlhelm, Brodie, and ACH were not found to be statistically different from each other. The study demonstrates that both the historical and current helmets have some primary blast protective capabilities, and that simple design features may improve this capability for future helmet systems.