in the case of the the M14 I would think you would be talking about either the Nam era M21 (*some* units still use it, but I'm not sure how many) or the M25 which is practically the same (to my understanding) as the M21 - both rifles are upgraded variants of the M14 match grade rifle...
personally I think as far as BF2 goes, I would enjoy using an SPR (hehe, Knights SR25) more than a match grade rifle of the M14 variant, even if it packs less of a punch, it would have (I think) better handling and less recoil...
BTW: you guys should check out
tapco.com and check out how they've modernized an old SKS with composite/plastic stock, picatinny spec RIS, and a reflex/dot-sight - I havent show it to my dad yet because it would make him jealous and want to trade his old wood stock SKS for one of those nice new composite build SKSs