I hand load 38 special. My powder is 7625. My bullet weight is 158Gr. I noticed in my load book that MEI Cast bullets loaded with 4.2 grs. have a velocity of 894 fps @16,100 psi and jacketed bullets loaded 4.5 grs have a velocity of 825 fps @ 16,300 psi. My question is how can a jacketed bullet loaded with more powder travel slower than lead loaded with less powder? Notice that PSI is higher on the jacketed