Well Marius let's be honest, how often will this happen?
Ok so it has happened, now what?
I always ask the question if you could not hit it in the correct place with the initial shot which would have been controlled, how on earth are you going to hit the sweet spot from the back?
I have always believed firstly that you should use a a caliber that is up to the task. For a PH this is even more important.
I also find it better to shoot at something you can see and not something that is at the other end of the animal especially when it is a wounded DG animal, therefore I would rather go for the anchoring shot in this case rather than attempt to reach a vital organ which I at best in this scenario will be quesing where to aim....
Yes this one is in the open and also offers a neck shot however for demonstration purposes they best shot to take is high spine shot(just above the root of the tail) or either of the hip joints, with a premium grade expanding bullet of course to maximize damage. Either shot will anchor the buff. These targets are easily seen from the rear end.
Reaching the vitals is very tricky shot from the rear. A shot from the rear that only hits a lung is just gonna piss the buff off more and increase the risk of a charge. In order to reach the heart from the rear you would need very impressive penetration and super shot placement, also much more difficult when the buff is slightly quartering from the rear. Probably only a Meplat heavy for caliber brass solid from a 458 or larger traveling at about 2300 will do. I know my 500 Jeff with 570gr Rhino solid @2300 will.
Very difficult shot to pull off. From the rear.
Below photo although not in the bush shows hip joints and root of tail much easier than shot for the vitals.
View attachment 358871
We had followed a Bow wounded Cape Buffalo for 4 1/2 hrs after waiting an hour before starting, we found him in similar position as below(could only see sweep of horn not shoulders and neck), although also in a thicket, it was hot wind was swirling, we had to act fast, 570gr Rhino controlled expansion bullet from 500 Jeff hit spine just above the root of the tail and buffalo could not regain his back end, allowing us to finish him off.
View attachment 358870
Personally I use premium grade expanding bullets(Rhino) for buffalo, in 500 Jeff it makes no difference if they are standing, coming or going, that combination flattens them.