The USASOC Sniper Comp is geared towards combat conditions, and the for at least the last three years, semi-autos have dominated the competition over bold actions. The past two years have been won by LaRue OBRs, and I believe this year was also won by guys running LaRue OBRs. The M110 and Mk11 rifles perform very well in most portions, but the outright accuracy of rifles like the OBR and other custom .308 ARs is hard to beat. .308 ARs are printing equal accuracy to the M24 and M40 bolt guns, but they have a much faster rate of fire with a higher magazine capacity. For military applications on the battlefield, the .308 bolt gun is pretty much obsolete.
It's for this reason that the Army is transitioning all M24s over to .300 Win Mag or .338 Lapua, and the USMC is going to be moving away from the M40 and going to the Mk13 .300 Win Mag rifles. For the extreme long range game, bolt guns still rule, but they have to be in the heavier magnum calibers.
In civilian competitions, bolt guns are still the big winners, but nearly everyone winning is using a .260/6.5mm cartridge. .308 rifles are pretty much obsolete in civilian competitions, unless they're an action/steel challenge type comp.