RE: Bolt not closing???
LA, A .38 will work OK, but might be a bit harder to keep lined up. I liked the .45 better as it located nearer the midpoint of the shoulder and was more stable.
The .003" increase you describe is a sign of rather high pressure. How hot is that load, and does it extract easily? I would think you would be having extraction problems. Also would like to hear if you found any need to lower your sizing die to touch the shell holder.