Sgt_Jamez
You are case forming using .223 brass and a lot of your problem is brass spring back, a second problem your going to have are thick case necks from using .223 brass.
If you shorten the die then after the brass has be shot and fireformed you will always have an air gap between the shell holder and the bottom of the die. When this happens you are going to have inconsistent shoulder bump and have cases with varying cartridge headspace length.
Keep lapping your shell holder until you get the cartridge headspace length you want with the die making hard contact with the shell holder and the press reaching camover. AFTER the cases are fireformed you can try a standard shell holder or the competition shell holders to get the proper shoulder bump with the die making hard contact with the shell holder. Again there is a very good reason the die instructions tell you to adjust the press to camover and that is consistent shoulder location.
A much simple solution that avoids forming problems and having thicker shoulders and necks that require neck turning or reaming is to buy .221 Fireball brass.
Remington Reloading Brass 221 Remington Fireball
If you are going to keep using your LC 5.56 brass then remember to pause for three seconds after the press reaches camover before raising the press handle. Then rotate the brass 180 and size again waiting the three seconds again, this reduces brass spring back and the cases will have shorter and more consistent cartridge headspace length.
DO NOT remove any material from the bottom of your die, the die length was designed for resizing "NORMAL" fired cases with brass spring back computed in. The brass spring back varies between brands of cases, annealing and how many times the case has been fired. Again "DO NOT" take any drastic steps with your die length until you start dealing with "NORMAL" length cases and finding out if forming from .221 Fireball cases are still to long. Think about it, is your die really too long or do you just have hard thick brass that doesn't like changing size.
Now continue to lap your shell holder and resize the cases "PAUSING" for three seconds, rotating 180 and resizing again and pausing again at cam over and then checking your cartridge headspace length.
Below, a Redding competition shell holder on the left and a standard length shell holder on the right. The Redding shell holder pictured is .004 taller than the standard shell holder and all my resized cases reach camover, and this is done for consistency.
