Thread: what causes differences in OAL with a comparator ?

I’ve found variable neck tension causes “spring back” when loading. I had this real bad in the last batch of 7mm rem mag I loaded. I could feel it in the press when projectiles were harder or softer to seat then the “normal”. The observation always aligned with my measurements immediately afterwards. Soft to seat were seated further in the case (a real prick when it goes beyond what you want) and hard to seat were seated too long and need an adjustment and pushed further.