ORIGINAL: cmscat50
... 30-06 is NOT good to 200 yards. Lots of drop and not much energy retention that far out.
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.300 WSM (winchester short mag) would be my choice although I believe the 7mm WSM is flatter and faster, just a smaller caliber bullet.
Check out the WSM calibers. The performance is unbelievable.
I suggest you check some ballistics charts. I am not saying the 300 win mag (or WSM) and 7mm mag don't have any advantages over a .270 or 30-06. The fact is though, that at 200 yards, there is absolutely no difference in effective trajectory or killing power. Drop for all, across almost all factory loads is virtually identical (at virtually 0, if sighted in properly 1-2" high at 100) and difference in power delivered is insignificant in terms of killing any N.A. game animal.
We could have this discussion at 300 yards, but you said 200.