What could cause this?

[DOGCAPPER]

Looks almost identical to a rifle that hung in Jacksonville, Fla gun club. It was ruined by an ammo mixup.
The details escape me now, but short case 30 cal was fired in a long case 25 cal chambered rifle.

 

[ebb]

Has the OP learned nay more about this gun and what cause this to happen?

 

[Rustystud]

check your headspace with ejector removed.
With steel go and no go gauge. Also check the previous fired cases in a case gauge. They may have fire formed into a new wild cat.

 

[AckleymanII]

Sounds like the dimension from the bolt face to the back of the barrel is off. .005-.007 is about right. I would bet you have .020 or a LOT more. I think that you could have made a miscalculation in eliminating the bolt nose recess on the barrel.

The dimension is more than likely off by the thickness of that wedge that was blown out the side.

Gunsandgunsmithing nailed it.

 

[Concha]

6.5x47 Chamber using Creedmoor Ammunition?

 

[Pres100]

Who chambered the gun originally?