The Best Hunting Cartridge Ever

Obviously certain cartridges are better for certain applications. However, almost all of us have wondered at some point or another what the best general purpose cartridge is. There have been hundreds of articles debating the merits of this or that cartridge. What those articles have failed to do is create a metric that allows us to compare cartridges of different calibers or shapes. In order to compare apples to apples we need a numerical measure that takes into account all of the cartridge aspects important to hunting. I will outline in this article my best attempt to do so.  

Cartridge Power

The first step to developing such a metric is to determine what variables are important to a hunting cartridges efficacy. An obvious starting point is how powerful a cartridge is. In my article on the Killing Power Score we evaluated how hard a cartridge hits using three variables.  

To summarize, the first variable that we decided was relevant was kinetic energy at 100 yards, which tells us how much damage the cartridge has the potential to inflict. Next is the sectional density, which is a measure of how well the bullet will penetrate, velocity and contruction aside. This is important because even if a bullet has an enormous potential to inflict damage, if it is unable to get to the vitals and damage important tissue it is all for nought. Finally, we took the frontal area of the bullet. This determines the size of the hole, which is an indicator of blood loss, another mechanism for killing.  

However, the power of the cartridge is only one half of the measure of the cartridges effectiveness. If the only meaningful measure of a cartridges power was the killing power, everyone would shoot a 50 BMG and this entire discussion would not exist. The other relevant measure of a cartridge is how easily it can be shot accurately.  Just like estimating the power of a cartridge, we identified variables that would contribute to how ‘shootable’ a cartridge is.  

Ease of Use

First of all, the trajectory of the cartridge effects the ease of hitting targets at distance. Even with advancements in range finders and optics, it is still easier to hit a target at long ranges with high velocity bullets. This is because the bullets arrive at the target faster, allowing gravity and wind less of an opportunity to impact trajectory. As such muzzle velocity is one of our variables affecting shootability.  

Another thing that affects trajectory is the ballistic coefficient. More efficient designs lose velocity slower and fly through the air more efficiently. This results in less drop and less wind drift, making it easier to put rounds on target. Subsequently, the G1 ballistic coefficient of a typical loading for the cartridge is the second variable that impacts trajectory.  

Finally, the third and most important characteristic of a cartridge that affects accuracy is the recoil generated. While different shooters can tolerate different levels of recoil, virtually everyone shoots lower recoil cartridges better. Recoil can be measured as ft-lbs of recoil energy in a 7.5lb rifle, which is a fairly typical weight for a general purpose hunting rifle. 

Combining the Variables

So in order for a cartridge ro perform well, it must have a high KPS and be easy to shoot. In order to calculate ‘shootability’ we will multiply the velocity with the BC and then divide by the recoil energy. However, at common hunting ranges velocity has a much bigger impact than ballistic coefficient on the trajectory. To compensate for this, we will take the 20^th root of the ballistic coefficient. This reduces the relative effect of the BC to around 10 percent of our final shootability measure. I believe 10 percent variation is much closer to the actual effect of BC from 0-500 yards.  

This leads us to our final formula giving us a score ranking cartridges for general purpose hunting. The formula is as follows: 

Score = KPS*SS 

= (K_e*S_d*F_a)*[(M_v*(BC^0.05))/R_e]

Where K_e is the kinetic energy at 100 yards in ft-lbs, S_d is the sectional density of the bullet, F_a is the frontal area of the bullet in square inches, M_v is the velocity at the muzzle in fps, BC is the G1 ballistic coefficient, and R_e is the recoil energy in ft-lbs. 

This should give us a score that weighs the power of a cartridge with how easy it is to shoot. Because we multiplied instead of added, a cartridge must be reasonably strong in all of the variables to do well. This is because a score near zero in any one variable (besides recoil energy) will cause the final score to be near zero. Likewise, a very high recoil score will counteract high scores in all the other areas. This should give us a list of the cartridges that offer the best trade-offs between power, recoil, and trajectory.  

Results

After ranking all fifty cartridges, the results are in. The greatest cartridge is… the 300 Winchester Short Magnum! The top cartridges tended to be short action cartridges with steep shoulder angles, typically using heavy for caliber bullets. This makes sense, as these short action cartridges burn powder more efficiently. This means they are creating high velocities in proportion to the level of recoil. The heavy for caliber bullets have high sectional densities and ballistic coefficients, leading to good penetration and strong trajectories. Below I have included a table of the top 50 cartridges and some of the relevant numbers:

Closing Thoughts

The purpose of this article is not to tell you which cartridge to buy. Instead, it is intended to quantify a cartridges merit using measurable objective parameters. Consider this calculation a tie breaker or starting point rather than gospel. Only you know specifically what is best for your specific hunt. Hopefully though, you found this an interesting, and potentially different way to evaluate a cartridge.