Why Deer Rifle Calibers Don't Matter (Much)
The South Carolina DNR has published an interesting article by wildlife biologist Charles Ruth, based on an extensive SCDNR deer hunting study. This article can be found at http://www.dnr.sc.gov/wildlife/deer/articlegad.html in its entirety. One of many factors tabulated in this survey was the distance whitetail deer traveled after being shot, grouped by caliber. The results by caliber are as follows:
Based on these results, the report correctly concludes that, statistically, there is “No difference in effectiveness of the various calibers.” The problem with this information is that it is incomplete. From a hunter's perspective, caliber does not adequately define the cartridge. Thirty caliber deer cartridges, for example, cover a huge amount of ground, from the .30-30 to the various .300 Magnums There is a significant difference in typical bullet weights, sectional densities and velocities, none of which was tabulated in the SCDNR study.
Anchoring an animal isn't the same as killing it. Though a spine shot certainly incapacitates, it does not kill quickly. While a brain shot may 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.
At 200 yards, typical energy levels for common deer hunting rifle loads are as follows.
Although there is often a predisposition to caliber worship, from a practical perspective there is no basis to show that one cartridge is any more effective than another. Deer are fragile animals, considered medium game (CXP2). From a practical standpoint, anything that kills a human being can kill a deer.
For those with practical backgrounds, the reality that a 40 grain, .22 LR bullet from 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 pound, Grade 1-3 steer will give you 750 pounds hanging weight and produces 505-530 pounds of retail cuts.
Alhough we like the idea of bullet expansion, that notion can mislead. A 100 grain, .243 Winchester bullet with 85% expansion still does not achieve the diameter a .45-70 projectile has before impact. Large diameter bullets don't shrink in flight. 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 energy numbers, the .44 RemMag has proven to be an effective whitetail round.
Caliber and cartridge do matter, of course, but not in the way they are often marketed. Exterior ballistics can be summed up neatly as “time of flight.” The shorter the time of flight to your target, the less time wind drift and gravity have to work on your bullet. The two ways to achieve this are increased muzzle velocity (and recoil) and aerodynamically superior bullets that are less affected by wind drift and velocity erosion.
An animal is killed by disrupting circulation or destruction of the central nervous system. If the mass and sectional density of the bullet is insufficient to penetrate, particularly after a high-speed collision, we can have problems. The .220 Swift of 1935 is a good example. With a muzzle velocity 1400 fps faster than 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 grain, .224" projectile (SD only .142) became evident.
Once you get to at least a .24 caliber bullet of reasonable sectional density (about .218), construction and sufficient impact velocity to destroy blood-bearing organs and quickly end circulation, the differences in killing power become minor on a light and fragile animal like a whitetail deer. We might like to think that at 150 yards, the maximum range at which an estimated 98% of deer are taken, there is a huge difference between a relatively low energy .30-30 and a more than double the energy .300 Magnum. However, there is actually no significant difference in killing power. Both are more than sufficient to take a whitetail deer quickly, cleanly and efficiently.
Of more importance to the hunter is a rifle's handling, fit and shooting comfort. These factors inspire confidence and contribute to good marksmanship. We all tend to practice more with guns we enjoy shooting 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 ergonomic 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 it is venison for dinner. If you fail to accomplish that, the rest doesn't matter. Fight a clumsy gun, heavy trigger, or a rifle that beats you to death with every shot and it isn't hard to figure out how these factors can destroy confidence, enjoyment and practical accuracy. One hundred percent game recovery goes out the window at the same time.
Copyright 2011 by Randy Wakeman. All rights reserved.