An adhesive wear failure mode is of particular concern when rolling bodies are operating in the boundary lubrication regime, and its occurrence is also sensitive to loading and temperature as well as the chemical interactions occurring on the rolling surfaces. In this work, the adhesive wear performance of two heat treatments, low-temperature temper (LTT) and high-temperature temper (HTT), of the case hardened martensitic bearing steel Pyrowear 675 was investigated using a ball-on-disc apparatus in an all-metal and hybrid configuration with a silicon nitride (Si3N4) ball. Adhesive wear results obtained with an AISI M50 disc were used as a baseline for comparison. A material with previously studied poor adhesive wear resistance, Cronidur 30 (CR30), was also investigated. Tests were conducted at a temperature of 200°C and maximum Hertzian stress of 1.95 GPa. An MIL-PRF-23699 oil with a nominal viscosity of 5 cSt at 100°C was used as the lubricant. In the test protocol, different lubrication regimes were explored by varying the entraining velocity from 10.75 m/s down to 1.27 m/s at constant values of percent slip (15%, 30%, 50%, and 70%). Traction curves and optical microscope images were used to determine the occurrence of adhesive wear. Additionally, scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) was utilized to examine the wear tracks. The all-metal tests revealed equally poor adhesive wear resistance in both tempers of P675 relative to the M50 baseline. In the hybrid configuration, all the tested materials exhibited excellent performance except for CR30, which was the only hybrid to see an adhesive wear failure. It is noted that when paired with Si3N4, the adhesive wear resistance of Pyrowear 675 is seen to be equal to that of all-metal M50.