Carpenter Custom 465 Stainless alloy, a high strength PH stainless steel, was recently introduced to the Aerospace community. Because of its combination of high strength and corrosion resistance, this alloy can be considered for a number of aerospace applications. Potential uses for the alloy include a higher strength replacement for 15-5 PH parts, and a drop-in corrosion resistant replacement for 4330M or 4340M parts. The use of this alloy would eliminate need for environmentally damaging corrosion resistant coatings or platings currently in use on low alloy steels. In addition, Custom 465 Stainless alloy offers airframe manufacturer fabricability benefits compared to the use of alloy steels because machining burns and/or heat treatment decarburization are no longer issues. In order to be qualified for airframe use, additional testing of the alloy’s environmental cracking resistance, including slow strain rate tensile testing and stress corrosion cracking resistance (KIscc), were desired. Stress corrosion cracking resistance can be determined using different test methods and test samples. A test program was set up, with the object of comparing two test methods to ultimately identify a technique that would provide specific KIscc values that could be used for design purposes. The results of this test program, comparing a standard ASTM test sample, which is a bolt-loaded wedge-opening-loaded (BWOL) sample, with the standard NACE test sample, which is a wedge-loaded double cantilever beam (DCB), will be discussed. Many large aerospace parts are produced from forgings. One material characteristic that can influence mechanical properties of a finished part is grain size. Some concern to the aerospace manufacturer are areas of forgings where grain coarsening could occur due to flow patterns or dead zones during forging. The effect of grain coarsening on the tensile, Charpy V-notch, and fatigue properties of Custom 465 Stainless alloy were investigated.