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.
On the other hand, when chambered in a carbine, 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 firearms enthusiasts and utilized by militaries worldwide. It is accurate, has low recoil, and is chambered in many firearms. It can be used for hunting in some states, self-defense/home defense, target shooting, and competitive shooting.
The 9mm Luger is a pistol cartridge loved by countless firearms enthusiasts and militaries for different reasons. It’s accurate, has low recoil, and is chambered in revolvers, semi-auto pistols, and carbines. Its primary uses are home and self-defense, target shooting, and competitive shooting.
So which one should you own?
I own firearms chambered in both. But that’s not what this article is about. It’s about reaching a reasoned conclusion by comparing various aspects of the 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 an everlasting winner.
Technical Specs
As expected, these two cartridges have some drastic differences, making them easy to distinguish at a glance.
The 5.56 NATO bullet has a bullet diameter of 0.224”, whereas the 9x19mm is loaded with a 0.355" diameter bullet. The 9mm is also loaded with heavier bullets than the 5.56 (with rare exceptions, e.g. Liberty Ammunition Civil Defense 9mm 50 grain SCHP).
The 9 mm case and overall length are over 1” shorter than the 5.56x45, which also helps explain the 5.56’s more-than-double case capacity. The maximum pressure of the 5.56 is 55,114 psi, whereas the 9mm’s is only 35,000 psi.
Now that we know just how different these cartridges appear, let’s see how they translate into real-world situations.
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 will 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. On the other hand, free recoil is a more objective measure of how hard a cartridge kicks based on firearm weight, muzzle velocity, propellant weight, and bullet weight.
Neither cartridge is known for 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, at 4.5 ft-lbs (the 5.56x45 generates significantly more recoil energy, but a 5.56 rifle’s greater mass proportionately absorbs that recoil). Most shooters won’t notice this difference.
While the 9mm technically has less recoil, it’s not enough to make a drastic difference. This category is a draw.
Continue reading 5.56 vs. 9mm: Carbine Caliber Conundrum on Ammo.com