"You must produce enough crimp to dig the end of the case into the bullet slightly to prevent the bullet .........."
Go to your room right now!
The .40 S&W requires a TAPER crimp die that essentially takes the belling out of the case mouth and makes it straight---same for 9mm, .45auto, etc. If you try to go too heavy on the crimp, you'll actually loosen the bullet tension. Norm Lee got it right, follow his advice.
Snuffy did, however, discribe the correct way to ROLL crimp a bullet in a revolver cartridge. The case mouth is crimped (rolled) into the bullet cannelure, which is there for that purpose. Keeps the bullet from loosening up during recoil. Since auto pistol cases headspace on the case mouth, we don't roll crimp, (even if it has a cannelure) lest there be no case mouth on which to headspace. The case must be properly sized to hold the bullet securely.
Actually the case rim is held by the extractor, so most don't reach far enough into the chamber to actually headspace on the mouth, anyway, and if you used a slight roll crimp, as suggested by snuffy, you'd be allright--but not if the bullet doesn't have a cannelure.
