Making four consecutive shots at a range of 950 yds (869 m) is indeed very good shooting, but is not in any way
magical. Clearly, this marine was
consistently applying the principles of marksmanship to make those shots. 900m (1000 yds) is generally considered the maximum effective range of .308 based sniper systems. The biggest weakness with the caliber is its vulnerability to get pushed around by the wind. Snipers shooting at that range require spotters with
excellent wind-reading skills for consistent performance. A point of interest, the article makes no mention of his spotter.
The system the marine was using, the
M40A3, seems a decent system with the obvious weak point being the Unertl scope. If it is the same model used on the
Canadian C3, which I think it is, then it is crap. It has a very limited windage adjustment, something like 9 Minutes Of Angle (MOA). If you are shooting into a 12 MOA cross-wind you need to use a comination of sight-adjustment and aiming-off. Hardly the ideal. There are a number of other problems as well.
Regarding sniper identification; The British Army started concealing the identities of their snipers in the late seventies after it was found that the IRA was reading copies of the base newspapers back in England and determining the identities of new snipers from photo-laden course graduation articles. When the sniper's unit would deploy to Northern Ireland, the IRA would send threatening letters to their families. The CF Sniper School adopted the same security policy in the early 80's (I think) as a result of the British Army's experiences. I can't imagine why the US doesn't do the same thing.