Thread: Over pressure signs ??

Case head separation is also (if not mainly) caused by too dry a chamber and case. The case needs to be able to 'creep' on the chamber walls to be able to spread the load evenly over the length of the case. That way nearly 10% of the thrust is carried by the case itself. If too dry/rough the case does not creep and the head starts to separate at which point the full thrust is transferred onto the bolt face. Without excess headspace this would take several firings to manifest if at all.

Full length sizing is a major culprit too.