I bought a new Rem 700 action (long action, magnum boltface) and I have been swinging back and forth between doing a 7mm RM or a 300 win mag. Are there any other good options I should look at? My goal is to have a hard hitting, accurate rifle out to at least 600 yards. I already have a 700P in 308 that shoots great even though I am a novice rifleman and want something that's a "step up" in energy delivery on target. The longest range I have access to is 600 yds currently. I would also like to hear reccomendations on barrel manufacturers, I have been leaning towards Krieger or Shilen just from what I have read.