I load 38sp, 357 and 40 calibers and I am a self-confessed rookie. To the OP, I use a Lee FCD with all three and I have had an interesting learning curve. Without all the gory details, I can say that the taper crimp adjustments I made with the 40's seemed easy compared to getting the roll crimp right with the 38 and 357.

When I finally became comfortable on the 357's, I found the die set just a bit more than 3/4 turn after initial contact against the mouth of the case. This seemed to slightly "roll" the edge into the cannelure of the bullet.

A while back on this forum, someone wrote that if I hold a completed case in my left hand and try to depress the bullet with my right thumb (hard)....I had sufficient crimp if it didn't move. I'll go with that.

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