First, I think the instructions say to turn the die an eighth of a turn (not an eighth of an inch) after it touches the shell holder.
Second, it seems to me that if you didn't get the case into the die as far as RCBS intended, the main problem would be that the distance from the base of the case to the shoulder could be too long cause you didn't squish it back.
If so, the bolt might not close all the way. So, I think the first poster asked the right question. Can you chamber the round?