Far from first. They were used & worn out by the hundreds in the first Iraq war, among other uses.
Canadian military snipers use 50 cal. rifles. In Afghanistan, in 2002, Cpl. Arron Perry broke the record for longest distance confirmed sniper kill -- his was 2,430 metres. He was awarded a Bronze Star by the U.S. for that (which did not make him popular with the then misruling Liberal government.)
And that's about all...
If I'm not mistaken, going back maybe a year ago there was a video on the internet showing a .50 caliber taking out a Taliban insurgent in Afghanistan. The shot was maybe 500 yards or so, one ridge to the next terrain wise, the victim lying prone on an outcrop was literally blown into the air and came down in pieces. Great video ...