Doug,
Are the Speer LRN swagged? Do they have a "criss cross" pattern on the outside of them? Dry lubed?

If so, the smoke you are seeing is from that soft lead and lube. All powders with that combination, well, maybe not Trail Boss, are going to smoke. Just the nature of the beast. If you want to reduce the smoke, get a good cast bullet, one that fits your particular firearm correctly that isn't too hard of soft and run them with 4.5gr of Unique in a 38Spl case, 5.0gr in a 357Mag. I will almost guarantee you that the smoke will go away.