Highly recommend to NOT use those slow powders in a .38. Blue Dot powder is too slow and it's faster than 2400-296-H110. You'll get wild velocity variations and possibly even a blooper load with a bullet stuck in the barrel. Seems that the primer force and powder ignition starts the bullet moving creating a much larger space for the slow powder to burn in which creates low pressure and velocity. Even a heavy bullet crimp won't help. I've seen these slow powders used and actually seen the bullets leave the barrel and land 20-30 feet away, followed shortly by one stuck in the barrel. Like I said, even Blue Dot is too slow for .38 special and I'd stay with the faster pistol powders even with 158gr. bullets.
