Shooting with the Mann: Ballistic Balance
Richard Mann 09.26.16
Ballistic balance, with regard to hunting cartridges, could be defined as those offering the most power and flattest trajectory, with the least amount of recoil, in a sporting weight rifle. Why is ballistic balance important? Balance is important in everything. If the tires on your pickup are not balanced, you’ll rattle out your eyeballs, and an unbalanced seesaw is kind of dangerous.
Let’s say you want to choose a big-game cartridge offering the best performance in all areas. How do you do it?
In terms of power, the average muzzle velocity of the most commonly used modern big-game cartridges is between 2,600 and 3,000 fps. With muzzle energy – another number often used to compare rifle cartridges – the average will be between 2,400 and 2,700 foot-pounds.
With regard to trajectory, sighted in at 100 yards, the drop at 300 yards of the most commonly used big-game cartridges will range from about 9 inches to as much as 40 inches. Something around 16 inches is a reasonable average.
There’s much more variance in how hard a rifle kicks. And, actual felt recoil is subjective and influenced greatly by the way the rifle’s stock is designed, as well as how it fits the shooter. However, recoil can be quantified in foot-pounds. From an 8-pound rifle, big-game cartridges recoil between about 4 foot-pounds, with a .223 Remington, to as much as 40 or more foot-pounds, with the big magnums. Interestingly, 18 to 20 foot-pounds of recoil is what most shooters will say is upper limit of their comfort zone.
Finally, we cannot forget the bullet is the determining element of power, trajectory and recoil. Most big-game bullets weigh approximately 55 – 300 grains, for an average of 177 grains. However, the most common big-game bullets weigh 100 – 200 grains, and that averages to 150. If we split the difference, we get 163.5 grains. In the interest of simplicity, let’s call it 165.
If we look for a rifle cartridge that fits within this band of balance, we find that a .308 Winchester loaded with a 165-grain bullet is an almost perfect match. An 8-pound rifle, chambered for a .308 Winchester, loaded with a 165-grain bullet is, what could arguably be called, a perfectly balanced big-game rifle. It hits hard enough, shoots flat enough, doesn’t kick too hard, and it kills with authority.
Incidentally, I’ve taken a wider variety of big-game animals with a .308 Winchester, loaded with 165-grain bullets, than any other cartridge. A single 165-grain bullet fired from a .308 Winchester put down a Montana whitetail at 318 yards, an elk at 345 yards, and a Newfoundland moose at 210. I also watched my son (below) collect a kudu in Africa with one shot at a stunning 465 yards. Don’t make the erroneous assumption that you need a magnum cartridge for big game.
Load a .308 Winchester with a good 165-grain bullet such as the Nosler AccuBond, and if you put that bullet in the vitals, the result on the killing end will always the same: meat in the freezer and horns on the wall. The result on the kicking end will always be the same, too: no bruises, no pain, and no flinch!