Among the games I've played, it's probably between the original Doom games (shooting in them just works) and F.E.A.R. F.E.A.R. also has great AI, so combat gameplay in general is great in that game. I imagine there are games with more satisfying shooting gameplay as well, but those are probably my top two. On the other hand, I didn't really like shooting in the 2016 Doom game, largely because it's constantly disrupted by glory kills which I don't even like (and gameplay in general is harmed by constantly being locked in 'arenas', but that's technically unrelated to the shooting mechanic albeit it's closely related).
If we switch the word 'satisfying' for 'fun' or something similar, I might also mention the Ratchet & Clank games. They don't necessarily feel all that satisfying for the shooting part, but using those weapons is still great fun.
