They will take about 3.1". Most have the mag blocked to 2.8'ish, but it's easy to get them to run at 3.05" or so. Perfect for the rounds you mention.

Anybody who seriously concerns themselves with the adequacy of a Big 7mm for anything we hunt here short of brown bear, is a dufus. They are mostly making shidt up. Crunch! Nite-nite!

Stolen from an erudite CF member.