Clearly his skull and brains shot out the back of his head.
That's not what happened. You don't understand ballistics.
I don’t think that’s what happened. Rather, the forces of shock waves in the tissues as well as exit wound forces pushed matter forwards, equal opposite reaction is rearward.
But, what I find most unusual is the projectile found on the turkey. The 160 grn round nose 6.5mm bullet is quite a penetrator. Neat huh, how a bullet that likely could penetrate several men winds up in the sheets...