In this paper, the research procedure is presented aiming at determining the impact of selected features and design parameters of the working unit of the hammer shredder on the rate of material circulation in the shredding chamber and its unit load. The addressed issues are new and very relevant, due to their scientific and utilitarian significance. In the available literature it is not possible to find answers to the research problems formulated in the paper. For the purpose of carrying out the work, a real-scale test bed was developed and constructed, where a hammer shredder equipped with a traditional rotor design with hammers in the shape of rectangular plates and a hammer shredder equipped with a new, original rotor design with hammers in the shape of a circular section were tested. The research was conducted while grinding granular material in the form of barley grain (spring Antek). Following the analysis of the experimental results, it was concluded that the new design solution of the hammer shredder rotor is more effective than the commonly used standard design solution and may bring significant economic and technological advantages. This is due to the fact that the new design forces the lower rate of material circulation in the shredding chamber and contributes to more efficient operation of the hammer shredder.