The 5.56 vs. 9mm debate is a tough one. In most respects, the 5.56 cartridge should outperform the 9mm. It’s a rifle cartridge compared to a pistol cartridge, after all.
But when they’re chambered in carbines, could these cartridges be more similar than they are different?
Let’s find out!
5.56 Compared to 9mm
The 5.56 NATO is a rifle cartridge beloved by many firearm enthusiasts and utilized by militaries worldwide. It is accurate, low recoiling, and chambered in many firearms. It can be used for hunting, home defense, target shooting, and competitive shooting alike.
The 9mm Luger is a pistol cartridge that is similarly widely favored. It is accurate, has low recoil, and is chambered in semi-auto pistols and carbines alike. Its primary uses are home and self-defense, target shooting, and competitive shooting.
So which one should you own?
I own firearms (pistols, carbines, and rifles) chambered in both, and enjoy firing them all. Some of my 9mm and 5.56 firearms would make for a better home defense or hunting gun, while others are ideal for concealed carry. But that’s not what this article is about. It’s about reaching a reasoned conclusion by comparing various aspects of these rounds’ performance, including their recoil energy, trajectory, accuracy, ballistic coefficient, and suitability for self-defense.
At the end of this article, we will tally the results and announce a winner.
Specs Comparison
These two cartridges have some drastic differences, making them easy to distinguish at a glance.
| 5.56x45 | 9mm Luger | |
|---|---|---|
| Parent Case | 223 Rem | 7.62x21 |
| Bullet Diameter | 0.224" | 0.355" |
| Neck Diameter | 0.253" | 0.380" |
| Base Diameter | 0.377" | 0.391" |
| Case Length | 1.760" | 0.754" |
| Overall Length | 2.260" | 1.169" |
| Case Capacity | 28.5 gr H2O | 13.3 gr H2O |
| Max Pressure | 55,114 psi (SCATP 5.56) | 35,000 psi (SAAMI) |
Now that we know just how different these cartridges appear, let’s see how those differences translate into real-world performance.
What Are the Differences in Recoil Between 5.56 and 9mm Firearms?
Recoil is an important consideration when purchasing a new cartridge. A round with heavy recoil will be more challenging to control and slow the rate of your follow-up shots. Increased recoil also raises the potential for flinching.
Felt recoil varies from shooter to shooter and depends on firearm choice, stance, and ammo. Free recoil, on the other hand, is an objective measure of how hard a cartridge kicks. It is determined by four factors: firearm weight, muzzle velocity, propellant weight, and bullet weight.
Neither cartridge is known for having shoulder-thumping recoil. In fact, shooters often choose both because of their low recoil.
The 9mm has about 4 ft-lbs of free recoil, while the 5.56 NATO has only half a pound more. Consider this in light of the fact that the 5.56x45 generates significantly more recoil energy, although a 5.56 rifle’s greater mass proportionately absorbs that recoil. Most shooters won’t notice any difference.
While the 9mm technically has less recoil, it’s not enough to make a drastic difference. This category is a draw.
Trajectory
Because the 5.56 NATO is a rifle cartridge, it’s designed to be fired over much farther distances. A 100-yard shot with a 5.56 is relatively simple for most shooters to make consistently. The 9mm can cover that distance in the hands of a skilled marksman, but its poor trajectory compared to the 5.56’s would make that shot much more challenging.
When fired from a firearm with a sight height of 1.5", a 55 grain 5.56 NATO bullet can easily be zeroed in at 100 yards and exhibit -2.9" drop at 200 yards.
In contrast, a 124 grain 9mm bullet fired from a handgun with a sight height of 0.5" and zeroed at 25 yards will have a bullet drop of -12.0" at 100 yards.
To be fair, this isn’t an apples-to-apples comparison. The 9mm has two disadvantages. The first is the nature of the handgun’s shorter barrel; the second is its slower and heavier bullet.
Even when we try to make everything as even as possible, such as firing a lighter 9mm projectile and using a carbine for both cartridges, the 5.56 NATO will still have a flatter trajectory.
The 5.56 easily wins this section.
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