Ninny,
The feed cone depth is headspace related. You can have correct longitudinal headspace and still have the case rupture because there is too much space around it - the case is too narrow or the chamber too wide. As shooters we more often refer to longitudinal headspace because it is easy to measure. And if horizontal headspace is OK then typically axial headspace is also.
There is still plenty of pressure in the barrel to do mischief as the carrier unlocks and the bullet is still in the barrel. Especially in a short gas system with a slow powder. Yes, the pressure drops as the bullet heads down the barrel but in this scenario it is still 39K lbs at the port, down to 16K lbs the muzzle (Ref: QL)
The feed cone depth is headspace related. You can have correct longitudinal headspace and still have the case rupture because there is too much space around it - the case is too narrow or the chamber too wide. As shooters we more often refer to longitudinal headspace because it is easy to measure. And if horizontal headspace is OK then typically axial headspace is also.
There is still plenty of pressure in the barrel to do mischief as the carrier unlocks and the bullet is still in the barrel. Especially in a short gas system with a slow powder. Yes, the pressure drops as the bullet heads down the barrel but in this scenario it is still 39K lbs at the port, down to 16K lbs the muzzle (Ref: QL)