I had a partial case head separation using a 1.8oz buffer

[JASmith]

Extremely unlikely - bullets jammed in the lands raise the pressure/velocity, but nowhere near blowing out the base of a case. Some bench-rest shooters deliberately load their rounds long so they jam into the lands as the bolt is closed.

Check your QuickLoad manual and you will see that the bullet in contact with the lands raises the pressure by 5,,00 or 6,000 psi compared to the same load with a jump.

Couple that with an already warm load and one can get truly uncomfortable pressures.

Regarding shooters’ practice of loading the bullet long, that practice generally also includes working up the load with the bullet in the lands. That allows the shooter to find a load with slightly less powder and get acceptable pressures.