Free: Contests & Raffles.
Broken rib punctured the guts on the roll down is my guess
My guess would be a fragment or the bullet clipped the esophagus, and in the tumble GI content was forced back up? I had similar on a double lung shot on a mule deer buck that tumbled 30 yards down a steep bank - actually had gut content come out his mouth, and gut content in the thorax. The diaphragm wasn't penetrated.