Bigger Bullet Better?
When it comes to hunting rifle performance, a bigger bullet aren't always better.
“Bigger is better” is a common misconception and an understandable one. You look at a big bullet such as a 500-grain flat-nose atop a 470 Nitro Express and you can’t help but be impressed. How can a bigger bullet like that be anything BUT powerful?
How Can a Bigger Bullet Not Be Better?
Well, I can tell you how: by not moving very fast. A bigger bullet gets its power, its punch, from not only mass, but also velocity. The mass, obviously, is the weight of the bullet. That comes from not just its width and length, but the density of its material. You could have a 50-caliber, 3-inch long bullet made of marshmallow and it wouldn’t be nearly as deadly as a tiny 17-caliber lead bullet less than 1/4-inch long and moving at the same speed.
So if mass is good, a 500-grain lead-and-brass slug from a 470 Nitro Express should be really, really deadly. Well, yes, it can be. They don’t hire these to stop charging elephants for nothing. But…
Without velocity, even a 500-grain bullet isn’t very powerful. Set one on your toe and big deal. But drop it on your toe from six feet up and ouch! Velocity from the pull of gravity has added something significant. Drop it from 12 feet up and it will hurt even more. That's not because the mass increased, but because the velocity increased, making the bigger bullet even better.
If you double mass, you double energy. If you double velocity, you quadruple energy. And therein lies part of the “magic” of small bullets at high speed. Speed does, indeed, kill.
Bigger Bullet Ballistics Tell the Tale
To demonstrate this, lets build ballistic tables based on the same bullet at varying launch speeds. We'll shoot a Hornady 178-grain ELD-X from a 300 Winchester Magnum at a standard muzzle velocity (MV) of 3,100 fps. Then we'll shoot the same bullet at half speed.
300 Winchester Magnum, Hornady 178-grain ELD-X, BC .545 at normal Muzzle Velocity:
300 Winchester Magnum, Hornady 178-grain ELD-X, BC .545 at half-speed Muzzle Velocity:
Notice how muzzle energy is four times less. The 3,798 foot-pounds energy of the 3,100 fps bullet drops to just 950 f00t-pounds in the 1,550 fps bullet. Half the velocity, a quarter the energy. Notice also that drop increases by about 4X, too, but remaining velocity and wind deflection change at differing rates.
Now let's see what happens with energy when we keep the MV at 3,100 fps, but reduce the mass of the bullet by half. Since this is a hypothetical situation, we'll leave the BC number the same, even though this would be nearly impossible.
300 Winchester Magnum Mythical 89-grain bullet half the weight of the 178 ELD-X, BC .545
Well, I'll be... this 89-grain bullet, half the weight of the 178-grain bullet but launched at the same MV carries, just as predicted, half the energy.
Can Light Bullets Beat Bigger Bullets?
Does this mean that we can shoot an extremely light hunting bullet and get the same results as we would with a bigger bullet? Well, sometimes. But not always. Bullets need other qualities besides kinetic energy. They must have enough structural integrity to resist breaking into tiny particles. If that happens, all their energy dissipates over a wide but usually shallow area which might lie well short of the vital organs deep inside an animal's chest. They must expand to create a broad wound channel, but not too much or the friction might slow forward progress before all the vitals are reached. But if they don't expand, they could zip right through like a target arrow, doing little damage. An effective hunting bullet is a compromise of mass, materials and construction engineered to perform properly at certain impact velocities, and those are four parameters difficult to blend and balance. Bigger bullets can be better, but so can faster ones.
Ron Spomer has hunted with bullets from calibers .14 to .73 and velocities from 600 fps to 4,200 fps. Each has taught him a little bit about real word performance. But he's still learning.
