Are you sure you didn't get a bad batch of W231.They say it is case sensitive but not that bad. Have been using 231 in all my .38s but have to say not used that light a bullet to much.I have used the 125 grain with 4.3 of 231 and had no problems.I load 148 HBWC using 3.4 to 3.7g and the 158 swc with 3.7g and have never seen this problem.By tipping the gun I can feel some difference in the recoil but not enough to make any different.You are getting your bullets in deep enough and what primers do you use all I have always used winchester.Didn't check the books but is 5.0 getting up there?? You can always go to TITEGROUP it should fire anywhere IS NOT case sensitive I use it in my .45colt and 6 grains the case looks empty