Are you absolutely sure on lengths? Did you measure every round to the ogive?

Sounds to me like you were seated 0-.003 off the lands and getting pressure spikes from slight variations in length. Do you use a OAL gauge and a quality set of calipers using a comparitor to measure off the ogive?

So dies dont repeat as well as others. Also bergers require special seating stems which often are sold seperate. You may be getting a ring on the bullet where the seater presses against the bullet. Others may see smashed tips.

I would either back the die off another .005 or run them jammed for ladder testing.
jammed will show max pressure at the lowest possible charge weight. Personally I haven't done that.