The hydro makes a .375 hole coming and going just like any other solid. I used them with no issues on the suni and duiker like any other solid. An A-Frame might have disemboweled either. Looking at the Nyala and waterbuck, I would guess the cup frontal inflicts twice the internal damage of a flat head solid such as Federal's Hammerhead. The Swift A-Frame hits with more immediate authority, and causes more - though not necessarily more lethal - immediate damage. It also will not typically exit a large animal like a buff or eland. Not a bad thing on a normal first shot presentation, but it takes a raking shot off the table. On my buff, the A Frame was under the offside hide. The shot took out everything across the top of the heart. Had I hit him with the hydro in the same place, the bullet would have exited and taken out almost everything above the heart. He might have gone another ten paces before piling up.
Hydro's negative is a pass-thru in a herd. Positives are a pass-thru on every other occasion (much easier blood trail) and turns the rear raking shot into a lethal option on even the largest game. They also shoot into one ragged hole in my R8.