and a little at a time until you remove the bell (just enough to remove the bell too much and you turn your gun into jammomatic)
lower the center of the die to touch the top of the bullet that you have already set to the correct o.a.l. tighten down these settings and viola .
shiny new bullets with no wrinkled sides.
btw if you can take a belled brass and shove the bullet in with your thumb you probably have a case sizing die out of specs (this also has already been said just wanted to agree with the other members)