Someone correct me if I'm wrong, but I believe the .410 shotgun is actually a "caliber", not a "gauge". That means it's a .41 calber. If the 1/2 oz slug is moving at approx. 1800 fps (as per a previous post), then it would have more energy than my .41 magnum handgun, which is normally considered adequate for deer at ranges under 50 yards or so.
IM jaybe