Fairly new to reloading and purchased a quantity of bi-metal RN with concave base bullets. I have manuals from Lyman, Hornady and Speer as well as reloading info from Allianz, but can’t find any recipe specific to the concave base design. The bullets measure .602 - .604” in length, and tend to run a few (3-5) grains light in weight. Other comparable FMJ projectiles I have measure .550 to .560” length. Have tested using W231 4.1 gr, 4.2 gr, 4.3 gr, 4.4 gr and 4.5 gr WSP, FED 100, CCI 500 primers COL 1.148, 1.140, 1.137 At present I only have CCI 500 primers available. All variations passed plunk test, cycled and fired successfully in Springfield hellcat. XDM compact, XDM OSP and KelTec Sub2000. The lower charges ejected ok, but for the most part at my feet. The longer 1.148 COL resulted in many cases with heavy soot. Was most pleased with the accuracy with the W231 4.4 gr, WSP, 1.137 COL loads which was my latest test. Any suggestions will be much appreciated..