I have a few light 38 spl loads that are very acurate and fun to shoot. The slowest is a Lee TL 358-148gr wadcutter on top of 2.1grs of Trailboss. Straight wheel weight lead lubed with a heavy coating of Johnsns Paste wax. It shoots very clean and accurate at 570fps with a standard deviation of 19.1. How slow have you gone without a squib load?