Years ago, when Leupold/Stevens owned the major stake in Nosler, there was a transition in either the guiding metal formula or the lead/antimony content. Most 30 cal BT's grew an additional 1/16" in OAL.
What was safe with the previous Lot, became jammed into the rifling at the new dimension if the die wasn't adjusted accordingly. Luckily I always run a loaded round into the rifle to see if anything changed. The boxes were different, I still didn't measure the bullets until AFTER I stuck a bullet.
Since then, I have seen very little variance, but I only check comp bullets mostly these days.
Cheers.