Sako 85 Finnlight 270 blew up

Definitely not an experience I care to repeat.

I am glad you are OK.  The damage looks like case head separation, but I am not an expert.

ILya

 

I tend to agree.   The rifle should be designed to handle a ruptured case better than that.  It's interesting the barrel looks unharmed.  I saw a Ruger with a case head seperation at my local club 3 years ago and it basically amounted to soot around the receiver vent hole and a little on the stock.  The rifle was fine and shot the rest of the day.

 

Not true.  I've seen rifles with the entire bottom metal blown out due solely to case head separation.  I've heard reports of extractors blown completely out of actions due to case head separation.  This is the reason some action designs such as the Remington 700 have completely enclosed, counterbored bolt heads that extends into the chamber end of the barrel.  The Sako doesn't have an enclosed bolt face, so in the event of a case head separation, the rapidly expanding gas is vectored out the bottom left side of the bolt face.  Even though the round may have been within normally safe pressure limits, we're still talking about more than 50,000 psi here!  The gas has to go somewhere, so it travels the path of least resistance, which on the Sako is down through the magazine and along the left side (from the shooter's perspective) bolt race.  This would explain why it blew the bolt shroud off, because the shroud is blocking the open end of the bolt race.  The amount of damage caused depends on the action design and the amount of peak pressure involved, so no two circumstances will necessarily have the same end results.  The fact that the barrel wasn't damaged supports the idea that it was caused by case head separation.  Seeing the brass will tell the story.  Usually the brass forward of the web ahead of the rim will still be in the chamber if it was caused by head separation.