As much as I like some Lee products, I would not recommend their factory crimp die on the .38 Special. That carbide sizing ring squeezes the outside diameter of the entire loaded round down to some minimum dimension.
That hasn't always been the case in my experience. If your round is at the point that the die is actually sizing it down, it likely wouldn't chamber in your gun either. Most of the time -- nearly all of the time -- if your ammunition is already within dimensional tolerances, the carbide sizer won't touch or alter your rounds at all. The die will simply act as a conventional crimper.
