7WSM or 7RM are plenty to 600yds for deer. As long as its accurate, its plenty. A 160gr Accubond leaving at 3000fps still has nearly 1700fpe at 600yds (at 5000ft elevation). Thats enough for a lot bigger animal than a whitetail when hit correctly.
If some is good and more is better, then too much is just right.
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