I compared bullet weights and BC's from what list listed on Speer's page versus Federal and they don't match up, so my guess at this time would be that the fusion bullets are different, from what Speer lists on their site.
I have been shooting a new bonded tipped bullet in my 15.75" center-grip 308 Winchester, XP-100 for a upcoming antelope hunt.
Speer of all things...172 grain Impact bullet.
With a chosen load and seated deep I still shot around half MOA off of a Harris bipod and small field bag, and it shot...
Have the throats been uniformed?
Grouping at 25 yards?
Try several groups with all 3-shots or all 6-shots from the same cylinder-Mark it with a sharpie to make sure you are using the same one.
Curious as to what that brings you in terms of accuracy.
The way we did load development when I was doing my 500 yard 357 magnum steel goal, was chronoing our loads changing the crimp tension until we got into single digits. Thinking we might have used the lee crimp die...That has been a minute since we did that.
How are your groups on paper at 100...