Are you trying to seat the bullet and crimp in one step? By "bulged" cases, do you mean that the cases are "crushing", or that the bullet is bulging them?
Reloading for the .380 is just like reloading for the 9mm, the .40 or the .45ACP. I've been reloading the .380 since about 1989.
I gave up on 1-step seating/crimping a long, long time ago. Differences in case thickness caused that to be an exercise in frustration. Especially if you're reloading mixed brass, it's nigh impossible to seat and crimp at the same time.
I have a set of RCBS taper crimp .380 dies. When setting up the seating/crimp die to seat the bullet, I screw the die down to the point where it just contacts the case (ram fully in the UP position), then back it off a small fraction of a turn and tighten it down. Here, I set my bullet seating depth with the seater plug. After I've charged and seated all of the bullets, I back the seater plug out all the way and screw the die body down to set the crimp in a separate step.
I use this method for all of my reloads, and I've never had an issue with bulging cases. If the die is screwed down too far, it can "crush" the case with too much crimp. I don't think this is what you're talking about...