Nick, et al.,
FYI, MIL_HDBK_5J has been cancelled and replaced with the "Metallic Materials Properties Development and Standardization (MMPDS)," DOT/FAA/AR-MMPDS. Fortunately, we had both Release G of MIL-HDBK-5 and MMPDS here in-house. The latter contained 13 or so graphs of S/N curves for 4340 steel plotted with the R factor set at 0 and -0.1--just what I had asked for. Many thanks!
-Dale