A fixed bolt action like the M-40A1, (Rem 700 BDL built to Match specs.) will always out perform a semi-automatic/automatic any day.
Even newer, finer developments of the fixed bolt design, have pushed the Sniper art form to much higher levels.
The 14 had it's place and has a loyal following, but I personaly, prefer being able to stick a round through a keyhole at 1,000 meters; Something a 14 couldn't even dream of doing.
While Rem 700 is my platform of choice for long range precision, I have to disagree with the above assertion. While true in the general sense, I have seen and shot AR15 match actions of various types that were essentially indistinguishable from a nice M700 with the same amount of money put into it. Or to put it another way, they can be so close in precision that the difference falls below the noise floor for anyone but the benchrest nazis (which have no place on a sniper mission). I've shot 1/4-MOA AR15s; when you are extracting that level of precision, the platform is entirely adequate for operational purposes and environmental factors will completely drown variations in precision from rifle to rifle.
Tangentially, I would love to get my hands on an AR10 that has been converted to 6.5mm. I hear they are all the rage on the long-range service rifle match circuits. I have boltguns in that cartridge (6.5-08 aka .260 Rem), and the cartridge is scary accurate at very long ranges. The prospect of a high-precision 1000+meter semi-auto makes me drool a bit...