The death moan happens more with archery kills then rifle, for whatever reason. Grizzlies tend not to moan as much when hit. I would describe a grizz as a very angry growl.
My first bear made a hell of a death moan, at least is seemed to me at the time.
I was extremely in experienced. My ears were ringing like hell from the three shots I took (first one did him in, the others were misses). Couldn't hear a damn thing, but through it, I heard the death moan. Threw me for a loop. Had never been told they did that. I looked at my dad and asked him "what is that?" "His death moan", he said. Immediately felt terrible and thought he wasn't dying fast enough. In actuality he didn't last very long at all. But made me consider, as we drove home, that I might not want to shoot another bear.
Fast forward a few years, I shot my second bear last June and don't even remember whether it moaned or not. And didn't feel bad at all. Just soaked the whole experience in. (I also get my muffs on before shooting. Much nicer to revel in success when you can hear)
I had one moan on a double lung. ran a little ways then flopped over and started that horrible noise. I knew they do sometimes but its still pretty disturbing.. like a bawling child. I put another shot behind the ear to make him stop.
I was watching a African hunting show and the ph (professional hunter )said that the only animal that has a different death moan besides the North American black bear is the Cape buffalo.
Ya I had a bear moan after the shot a few years ago. He went on for about 30 seconds. I understand that not all game dies the second it's hit , even with good shot placement but I didn't enjoy listening to that.