As you can clearly see, the hit was not taken by the halberd directly in the helmet, the impact was given by the wood part of the weapon. Always buy your helmet in a trusty armorer, saving 400 or less euro may take you to the hospital if lucky. Your helmet will save your live so... Please, don't save on that. This is a full contact sport and you may take a hard shot like this, this is why is so important to have the proper gear. Safety starts in you and with your gear, and the most important pie