In a previous blog we investigated the subtle differences between the 7mm Rem. Mag. and 300 Win. Mag. when firing optimum bullets in each. In this update, we’re going to investigate real-world performance differences among some readily available factory loaded ammunition. Factory loads don’t necessarily offer optimum velocities or the high ballistic coefficient bullets available to handloaders.
Study ammo catalogs and you’ll see there are usually 160-grain to 175-grain bullets offered aboard 7mm RM, but the 300 WM usually tops out at 180-grains with a few offerings at 190- or 200-grains, but rarely high B.C. forms. This is, I think, because most hunters are more than satisfied with the punch and performance of 180-grain slugs and aren’t eager to endure the additional recoil of heavier versions. Recoil differences between full-house 175-grain 7mm RM and 180-grain 300 WM loads are so minimal as to be ignored. But jump up to 200-grain bullets in the 300 and additional punch starts to open eyes — or close them.
Anyone planning on shooting factory ammunition in either of these magnums should study the market carefully before choosing between the 7mm RM and 300 WM. The differences in available loads could make one perform significantly better than the other. Here’s a sampling of currently cataloged 7mm and 300 WM loads from a variety of brands:
Clearly you’ll find more long range options (high MV and B.C.) in 7mm RM factory loads than 300 WM loads. Remember, the slower the MV and lower the bullet B.C., the poorer the ballistic performance across the board: more drop, more drift, less retained energy downrange. Also, the higher the MV and heavier the bullet, the greater the recoil. Consider all these factors when contemplating your options. If you never plan on shooting game beyond 300 yards, don’t worry about any of this. All of the factory loads above will suffice, as this video of a 6×6 bull elk kill suggests.
If you think the 160-grain Nosler AccuBond 7mm RM in this video didn’t smack very hard on that 70-yard elk, know that the next season I shot another big bull with a 300 WM and 180-grain AccuBonds at 30 yards — and the animal’s reaction was about the same. No rocking, no slamming to the ground. He just soaked up two rounds to the shoulder and one to the neck before wobbling and falling. Energy doesn’t kill; tissue destruction does.
If you’re looking for longer range performance advantages, choose carefully because there are huge performance differences among these loads. Some are designed for long range, some for close. Bullet B.C. makes a huge difference. Let’s run ballistic profiles on three. We’ll zero all rifles at 250 yards and shoot in a 10 mph right angle wind. You can study the data and decide which option you like best.
Grab a ballistic computer and run all the comparisons you want. Be aware that rifles/barrels can slightly alter manufacturer B.C. ratings, but these should get you close.
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