Jamesb's advice sound very reasonable. If I were you I would try to follow his suggestions. I love my NEF .223 It shoots very very good. Of course it isn't the prettiest gun in the safe but who cares. I have to keep James's info on file in case I get another NEF and it doesn't shoot.
Another tid bit for all you guys. - There is a product on the market called JB Compound which is excellent for "breaking in" a new rifle and for refurbishing an older barrel. It is a slightly abrasive barley paste that removes the tiny burrs in the rifling produced during the manufacture. It also cleans the stubborn build up from the rifling where the grooves and lands meet that accumulate over the years in older barrels that you can't see. You use this product sparingly. If you shoot alot, about once or twice a year is enough.
I had a 270 that shot like a house on fire when it was new. After 15 yrs or so, the groups started to open up. I thought I had shot it out but took it home one day after a session on the range. Ran some JB through it, cleaned it out and now it shoots great again.