I have previously experienced a similar result and was lucky enough to recover the bullet from the animal. Upon close inspection, it appeared that the meplat had necked over causing the jacket to shield the tip. It had impacted a rib on its way into the thoracic cavity. The wound through the on side lung showed no expansion. Subsequently, the bullet penetrated about nine inches in this fashion into the off side lung where inside of that lung it began to tumble exiting the offside lung sideways. It went through another rib sideways on its way out. It came to rest just under the hide on the off side in a banana shape having shed very little of the bullet.
After this singular odd experience, I wondered why and started searching for similar experiences and found a few. I started checking each bullet intended to hunt with a 0.038" wire drill and found a few that had some material inside the meplat or had jacket material that had migrated into the hollow cavity and obstructed the lead core.
Since including this simple step, in my experience, I have not had a single similar performance. Granted, I only have the opportunity to take six to eight deer a year and a handful of hogs so my sample size is limited to less than fifty.
After this singular odd experience, I wondered why and started searching for similar experiences and found a few. I started checking each bullet intended to hunt with a 0.038" wire drill and found a few that had some material inside the meplat or had jacket material that had migrated into the hollow cavity and obstructed the lead core.
Since including this simple step, in my experience, I have not had a single similar performance. Granted, I only have the opportunity to take six to eight deer a year and a handful of hogs so my sample size is limited to less than fifty.