1) Actors: as others have noted, Audie Murphy and Lee Marvin were both decorated veterans; there are probably quite a few others.
1) Character: LeBouef in True Grit, although he didn't shoot the handgun he carried, as he was all about the Sharps; still, he made a critical, long-distance shot after taking a mortal blow to the head. Hard to get tougher than that.
2) Noisy Cricket, Men in Black.