Thread: What causes this

Those cases are crumpled by 100 or 200 thou.

Yet, the bullet is seated right down into the neck - the ogive is at the mouth and its a long bullet.

So, I don't think its the bullet grabbing on a too tight / stcky neck. If it was, the bullet wouldn't have gone so far into the neck.

Something must be contacting the neck / shoulder itself. Its not just pressure on the bullet that's doing this.

The seating die was set far too short for those knackered rounds yet was apparently right for most of them ?

I've sometimes had the bullet seated about 100 thou too deep if the case isn't properly seated in the case holder. I have a co-ax press with sliding plates not standard case holders so its an easy mistake for me to make but perhaps it could happen if you got the base off line a bit in a standard setup ?

My 2c is to wind out the seating die itself from the press body using the lock ring. Then adjust the bullet seating depth by screwing in the adjusting screw for the seating stem into the die.

ps I've also had cases look like that after trying to size them by hammering into the wrong end of my lee loader !!