The high velocity of the NATO 5.56 mm causes the most damage (using military M4, M16, etc). The spin and speed of the bullet can be devestating. Once saw a round enter the elbow area, tumble along the bones, and enter the body cavity of a bad guy. KIA from being hit in the arm by a single round!!! It doesn't always happen that way, but it can.
However, the 5.56 mm round doesn't have any stopping power. In contrast, the 7.62 mm round can penetrate through walls, engine chasis, and other areas the 5.56 mm round can't get to. Very useful to have!
Uhhh... not sure how either relates to shooting toads, but I suppose you can give the pigs trouble!
