Chuck Guiteau
Graduate Poster
BStrong is right. Most well trained troops (and the US Army trains its troops well) use semi-auto fire when engaging targets at distance, and know fully well not to spray and pray. But when you have five or six enemy charging your foxhole at very close range, three shot bursts are worthless. You need rock and roll if you plan to survive.Except, as I recall, it was the not particularly effective method of prying and spraying that make selective fire with a 3 shot burst need to be added. Worried troops tended to expend much ammo to not much effect doing the full auto thing IIRC.
The same goes for house clearing. That's why the M4 is now made in two models, one with burst fire and one full auto.