My buddies future son-in-law is a seal sniper and he is now shooting a new sniper rifle the MK-20. He says it is a 7.62 rifle and that he has been hitting a 20 inch plate at 1000 meters. Here is a link to the rifle.
http://www.thefirearmblog.com/blog/2010/12/15/the-mk-20-mod-0-sniper-support-rifle-ssr/
http://www.thefirearmblog.com/blog/2010/12/15/the-mk-20-mod-0-sniper-support-rifle-ssr/