Had a CMP shoot last weekend and someone fired a 308 in a 7.5 Swiss rifle. No doubt his eye protection saved his eyes. He had powder burn around the eye glasses on his face with skin lacerations. While the 308 case swelled, it also cracked towards the base. It took about 2-3 minutes to see he was OK but initially he didn’t even know if he was OK so he just remained motionless.
It was a well known warning after WW2 to make sure a 8mm didn’t get fired in a 30-06.