In this picture you will see an "extra" ring by the primer pocket....that is the crimp...
Another pic showing this....
A pic showing a "normal" fired casing...
If you have cripmped cases they are really tough to re-prime after resizing because the chamfered edge around the primer is square....so it will not easily accept a primer.
You just have to "re-make" a chamfered edge in order for the primer to go in easier....a couple turns to remove the "squared off" material with the tool below will do it...
You likely will not run into this...but if you do like I did thats how you fix it.
LC