Question: what is a 7mm comparable to?
Answer: 300 Win Mag are pretty similar. ... 300 Winchester Magnum generally uses heavier bullets than the 7mm Remington Magnum. For instance, the vast majority of 7mm Rem Mag factory loads shoot bullets in the 139-175 grain range. Of these, 140 grain, 150 grain, 160 grain, and 175 grain loads are by far the most common.