When a .308 or .30-06 isn’t enough, most gunnies turn to the .300 Winchester Magnum, and that’s probably a mistake. While the .300 Winchester Mag is a step above the ballistics of the .30-06, it’s not a huge step.
There’s not a lot of practical difference between the two, at least not enough to be more than a few minutes’ discussion among knowledgeable riflemen. We’re talking 200 fps difference with 180-grain bullets. This makes very little difference in trajectory, though it would make somewhat of a difference in bullet performance at long range.
Rifle power may be succinctly defined by the velocity at which a cartridge can propel a given weight of bullet, and that’s a simple and universal way to compare cartridges. One quickly gets used to thinking in terms of “180 grains at 2,700 fps,” instead of lingering over indefinite but catchy cartridge names. If you factor in bore size, you can get a quick mental picture of the performance of any given cartridge. Also, you can quickly get a handle on any new offerings by the manufacturers, and can estimate their performance from the speed at which they drive their chosen bullet weight.
For example, if we are talking about .30-caliber cartridges that propel 180-grain bullets at 2,700 fps, we’re discussing the .30-06, or something very similar. If someone mentions 180 grains at around 2,900, you know they’re talking about the .300 Winchester, or something very similar.
The only gains from increased speed, for a given bullet, are flatter trajectory and the ability of the bullet to open at increased range because of the higher retained directional and rotational velocities. To put it another way, if your cartridge/bullet combo performs adequately for you at average hunting ranges, increasing the velocity a little bit won’t make the bullet kill a lot better.
Yet bigger is always better, or so we’re told. There will always be a market for the most of anything, be it bullet velocity or money spent on a rifle. Although the .30-06 has worked well on all big game for nearly a century, the .300 Winchester Magnum has been extremely popular as a second rifle for those who already had an .30-06. Still, the increased velocity is not a lot, and if we had an .30-06 we would not bother with a .300 Magnum, and vice versa.
However, what if we drive that 180-grain bullet at 3,300 fps? Wow! Now we’re talking HOT .30s. That’s 500 fps faster than a normal .30-06 load, which is a big jump in performance. Are there any cartridges that achieve that? How about the .300 Weatherby? Don’t forget the .300 Dakota. Anything else? Yes, the Remington .300 Ultra Mag will do that.
There are other hot 30 choices out there, but always consider the marginal difference between two rounds if you’re seeking to add a cartridge to your personal rifle catalog.
