Stainless maraging steel has been proven to be an industry standard material for plastic injection molds. Its high hardness and corrosion resistance extend the lifetime of the tool. This alloy system is also well-suited to additive manufacturing, which can be utilized to form internal cooling channels, further increasing tool life. Using Rapid Alloy Development (RAD) Oerilkon METCO is developing a new composition of stainless maraging tool steel that has high hardness/strength, is corrosion resistant, and has additive-capable melting and solidification properties. This study tests the hardness and corrosion resistance of the new RAD alloys against the current market competitor Corrax in hardness and corrosion resistance across different heat treatments. Hardness was measured using Rockwell C (HRC) and Vickers microhardness testing and corrosion resistance was measured using a potentiostat and salt fog spray chamber. Heat treatments were conducted at four temperatures and two times: 475, 525, 575, and 600°C at both 4 and 8 hours. The form of the novel and Corrax alloys in this study is a sectioned arc-melted ingot. Following testing, the novel alloys in peak-aged condition were harder than Corrax by around 5 HRC and had comparable corrosion resistance, verifying that the novel alloys would be competitive based on these properties.