Your friend is right that the .280 and .280 ai will do alot. Out to 300 yds there is not alot of meaningful gain in terms of killing effectiveness on the species your refering to if you do your part and use quality bullets. I favor a 7 mag for that round. I couldn't short myself by going the other way.

Go with the 7 mag, it's a little hoh hum, but as one guy said, it's because it's too new to be nostalgic and not new enough to create alot of excitement with the newer guys. But it leaves little to be desired or to be had in 7mm.

Proverbs
- A wise man feareth, and departs from evil: but the fool rages, in confidence.
- It is honor for a man to cease from strife: but every fool will meddle.
- Mischief is as sport to a fool: but a man of understanding hath wisdom.