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

[Zeneffect]

Playing devils advocate here... if it were an in battery blowout, would the resulting minimal damage be attributed to the short barrel length providing a quicker drop in pressure as bullet exits muzzle in a relatively quicker time?

Conversely, I'd we extrapolate this failure to a 20 inch barrel, would we expect to see more damage due to slower pressure drop off from the barrel length?