Gear pumps are widely used in hydraulic systems, particularly in applications requiring high durability and efficiency. This study explores the implementation of radial compensation mechanisms in internal gear pumps to enhance their volumetric efficiency and operational lifespan. The research focuses on modifications to the sickle insert, including the introduction of flexible tongues and a shaped piston mechanism, as described in patents P.431145 and P.431146. Experimental results demonstrate the impact of these modifications on pump performance, internal leakage, and pressure stability. Additionally, the effects of different materials, including bronze and plastics such as POM and PA6, on the pump’s efficiency and weight reduction are analyzed. The measurements carried out indicate that in the case of positive displacement pumps, a higher operating speed of the positive displacement pump increase the volumetric efficiency of the pump regardless of the material used to make the crescent insert. Changing the length of the cut made in the insert for type I and II does not change the volumetric efficiency of the pump within 1%. The study also highlights the influence of different materials used in the crescent insert. Among the tested materials, PA6 plastic showed better sealing properties compared to POM C by more than 1%, which led to improved operating efficiency and reduced energy losses. This finding suggests that careful selection of materials plays a key role in optimizing the performance of hydraulic components. The findings contribute to the optimization of gear pump designs for industrial and food processing applications, where fluid contamination resistance and noise reduction are critical factors.