As too something to shoot in to-I have personally used a sheet of plywood with a heavily compressed row of wet newpapers behind it--again- it needs to be compressed. If you follow this procedure and shoot into the center of the area ,you will recover the bullet for examination to determine its performance. You could also used wet phone books as well, again they should be compressed and in my experience, having the plywood in front is very helpful.

I have never had a problem with A-Frames and have used them on my last two hunts to Africa. I used factory A-frame loads in .416 Remington and hand loads in 300 ultra-mag--taking 3 cape Buffalo along with various plains game. Having said that, no one is perfect--Swift might have sent out a bad batch--I would definetly check performance before I left for Africa.
Good luck
Ripp