Some dies will not size the cases unless they are trimmed a little. You do not need to trim them to size before running them through the die, but take .015 to .020 off them then convert them then size to length. If you take off .020 before hand you should only need to remove an additional .010 to .015.
If you can not see the tyranny of having a gun ban enforced by men with guns... Then you fail to understand why the second amendment was written in the first place.