I've spoken to some of the folks that are hired to fight over there, in Kosovo and in Ireland. It is not always the rifle that is the winner. Those I know carry rifles of course and are well trained and well experienced enough to be hired for the expertise they have.
One of the things that they have found is that the bullet resistent glass of the HumVs that they use, are not even much blemished by the .308s that are shot at them. The rocks from the slings will often smash the windows so badly that they can't see out of them easily. The problem with the sling is that it is hard to hide and shoot from a little peep hole. During the two or three revolutions it takes for the sling to get up to full power, the rifle will usually take it's toll -- if the rifleman sees the slinger.
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