Why Deer Rifle Calibers Don't Matter (Much)

The South Carolina DNR has published an interesting article by wildlife biologist Charles Ruth. It can be found at http://www.dnr.sc.gov/wildlife/deer/articlegad.html in its entirety. In terms of distance traveled, results by caliber of the rifle are listed.

.243 (6mm) 40 yards

.25 14 yards

.270 31 yards

.284 26 yards

.30 33 yards

If the reader was inclined to accept this cartridge comparison without much thought, he might be readily conclude that the most effective whitetail cartridge is the .25 caliber by virtue of the average deer traveling only 14 yards after the shot, less than half the distance of .30 caliber cartridges and the .270 Winchester. Yet, despite presenting this information, the report concludes that there is “No difference in effectiveness of various calibers.” If this reads as immensely puzzling, it is only because it is.

The problem with this type of information is that it is horribly incomplete. A listing of cartridge caliber by itself ignores shot placement, range, and bullet type. There is no substitute for shot placement, of course. Note that the age, weight, sex, or health of the deer is not taken into consideration. Caliber also does not begin to define the cartridge. “Thirty caliber” covers a huge amount of ground, from the .30-30 to the .308, .30-06, .300 WSM, and the .300 WinMag. There is a significant difference in typical bullet weights and velocities, none of which is tabulated or factored in.

Wounding ballistic mythology is also perpetuated, as “knock-downs” are referenced. A bullet cannot knock an animal down with any more force than it can knock the shooter down, a matter of basic physics. It is so wrong and so pervasive it was debunked on the Discover Channel Mythbusters episode entitled “Blown Away.” Still it persists.

One thing that is completely missing from this report is the marketing hyperbole of “kinetic energy.” That's a good thing, as kinetic energy numbers redundantly screamed as being supremely important are not. Anchoring an animal isn't at all the same as killing it. Though a spine shot certainly incapacitates, it does not kill quickly. While a brain shot may well be the fastest kill, it is a comparatively small target and an unnecessarily high-risk, low percentage shot compared to the more generous double-lung kill zone. It also doesn't make for an attractive mount, to say the least.

It is a very small wonder that fundamental wounding ballistics, focusing on the disruption of vital tissue, are ignored in favor of marketing mythology. On the battlefield, expanding bullets are frowned upon as they are “inhumane.” In the hunting field, non-expanding bullets are frowned upon as they are “inhumane.” Since we can't begin to decide what humane is, it should be no surprise that cartridge and bullet selection for big game hunting remains a murky mess, even though we take 5-6 million deer every year.

We do need more hunters, though. It is hunters that fund DNR's, hunters that want healthy game populations above all else. Hunters, the original conservationists, saved the white tail deer from the brink of extinction. The over-crowding, crop depredation, deer-automobile collisions, and disease associated with overcrowding of today can only be addressed by good game management, and that means more hunters to help with the managing, not more Buicks.

At 200 yards, typical energy levels for common loads are as follows.

.243 Winchester 100 grain 1331 fpe

25-06 Rem 117 grain 1648 fpe

.270 Win 130 grain 1891 fpe

7mm-08 140 grain 1839 fpe

7mm RemMag 165 grain 2380 fpe

.30-30 Win 150 grain 967 fpe (Note: Hornady 160 gr. LeveRevolution 1306 fpe)

.308 Win 165 grain 1891 fpe

.30-06 Spring. 165 grain 2044 fpe

.300 WinMag 180 grain 2692 fpe

.44 RemMag 240 grain 672 fpe (rifle (Note: 571 fpe @ 100 yards handgun)

.45-70 Government 300 grain 1305 fpe

Though there is often a predisposition to caliber worship just because that's what we have or use, from a practical perspective there is no basis to show that one cartridge is any more effective than another. Deer are fragile animals, considered light game not big game by many, and anything that kills a human can kill a deer.

For those with practical backgrounds, the notion that a .22 rimfire out of a handgun can put a 1200 pound steer straight down every time is common knowledge. This is without the benefit of high velocity, heavy bullet weight, or a calculated energy number. That 1200 lb. Grade 1-3 steer will give you 750 lbs. Hanging weight and produces 505-530 lbs of retail cuts.

Though we like the idea of expansion, that notion can mislead. Our 100 grain .243 Winchester with 85% expansion still does not achieve the diameter of what our .45-70 Government projectile is before any impact. Large diameter bullets don't shrink in flight, of course. It was the .45-70 Government that took the American Bison and the grizzly bear to extinction in the United States, in a few short years. Despite the lack of any hammer of Thor mystical energy numbers, the .44 RemMag has proven to be a very effective whitetail round whether from handgun or rifle, with its .429 inch projectiles.

Caliber and cartridge do matter, of course, but not in the way they are marketed. Exterior ballistics can be summed up neatly as “time of flight.” The shorter the time of flight to your target, the less time for wind drift and drop. The two ways to achieve this are increased muzzle velocity (and recoil) and aerodynamically superior bullets, less affected by wind drift and velocity erosion.

An animal is harvested by ending circulation or destruction of the brain. If the mass of the bullet is insufficient to penetrate, particularly after a high-speed collision, we can have problems. The .220 Swift from 1935 is a good example. With a muzzle velocity 1400 fps faster than its rival, the .22 Hornet, it astounded the realm of varmint hunting. It was a magical cartridge for a time, inappropriately extended to big game hunting where the limits of a 50 – 55 grain projectile became self-evident.

Within reason, once you get beyond a 100 grain bullet of reasonable construction and reasonable impact velocity, velocity sufficient to destroy blood-bearing organs and quickly end circulation, the differences are minute, particularly on a light and fragile animal like a deer. Though perhaps we would like to think that at 150 yards, the maximum range that an estimated 98% of deer are taken at, there is a huge difference between a relatively slow, “low energy” .30-30 and a more than “double the energy” .30-06, there is no difference that is measurable. Both are more than sufficient to take a whitetail deer quickly, cleanly, and efficiently.

Of more importance to the hunter is the handling of the gun, the fit of the gun, and the comfort of shooting the gun. These factors all inspire confidence. We all tend to practice more with guns we enjoy shooting the most and avoid those that bruise or jolt us. Harsh recoil and anticipation of that recoil can destroy accuracy. For these reasons, moderate recoiling rifles with good handling characteristics, crisp triggers, and easy to use controls tend to get the most game. Within reason, the cartridge used is just a footnote in most deer hunting. Place an appropriate bullet in the right place and let it do its job, and it is venison for dinner. Don't accomplish that, the rest doesn't matter. Fight a clumsy gun, a heavy trigger, a safety that's hard to get off, or one that beats you to death with every shot. It isn't hard to figure out how these factors can destroy confidence, enjoyment, and take away field accuracy and one hundred percent game recovery at the same time.


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