An observation for you:

I shot cape buffalo, that was already down and was partly visible, at a hard quartering away angle, at a shallow angle through the spine. From entry to spine was +/- two feet. After the bullet, a 458 500gr Woodleigh solid had penetrated the spine you could see the bullets track below the hide (the buff was lying back up/ belly down but the onside was higher since the buff was lying on a slope). For about 8" it appeared true then the bullet obviously tumbled, spinnng more or less parralel to the ground and hide, a full turn and a bit more based on the track visible through the skin, and coming to rest visible under the skin and at about a 45* angle to the line of travel, which was straight the full length.

I figured the tumble was a result of the velocity loss from passing through 2' of muscle, the spine and another 8" of muscle. Initial distance was about 35yds; initial velocity about 2090fps. The bullet was perfectly round and undeformed with just a bit of lead pushed out the rear.

What are your thoughts?

JPK