Ross,
We've made no deliberate changes. What I mean is that the design and material components have not been changed. Every die we use eventually wears out. When we switch to a new die there can be slight differences that are the result of the bullet die making process (using EDM).
These differences are slight but you may find that you need to make tuning tweaks to get the latest lot to shoot. These changes will be slight and I suggest that you start with whatever worked before since you may not need to make any changes at all.
Regards,
Eric