When choosing a cartridge, there is very little room for error and regret—taking a good shot depends heavily on what you pick. Thankfully, our experts have tested the 9mm VS 5.7 for handguns and SMGS to give you a comprehensive comparison of the two. See the results below.
5.7 or 9mm?
In-Depth Comparison: 5.7 and 9mm
In order to solve the 5.7 vs. 9mm controversy, there are a few factors to be considered. Check them out:
The distinction between the 5.7 and the 9mm cartridge is glaring.
The 5.7 has a rebated rim bottleneck design, and the full cartridge is 40.5mm long, with its shell covering 28.9mm. Its bullet and neck diameters are 5.7mm and 6.38mm, respectively.
Its shoulder diameter measures 7.95mm, while its base and rim diameter measure 7.95mm and 7.8mm, respectively. The rifling twist of this cartridge is 228.6mm. You should note that the 5.7 has 12 types of cartridges.
The 9mm case has a rimless and tapered design, with a bullet of 9.01mm diameter fitted in a neck of 9.65mm in diameter. The rim and the base measure 9.96mm and 9.93mm, respectively. The cartridge measures 26.69mm in length, with the shell covering 19.15mm.
Our team of experts has verified the 5.7 to be way more accurate. It has a flat trajectory that powers its lightweight bullet so much that it delivers almost double the energy of the 9mm. Thus, the 5.7 has more close-range accuracy than the 9mm.
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One of the perks of the 5.7 is its ability to penetrate  through some thickness of Kevlar. Testing on body armor, the 5.7 was able to go through the front Kevlar and right about 5” into the jelly dummy.
The 9mm was unable to penetrate through the Kevlar. However, it got a penetration of about 10” when fired directly into the jelly.
The 5.7 got a penetration of approximately 14” when fired directly into the jelly.
The difference in the recoil of the 5.7 and the 9mm is pretty much noticeable. Firing the 5.7 from a Ruger-57 produces 35 percent less recoil than the 9mm fired from a Glock19. The 5.7 allows you to put rounds down range more accurately than the 9mm due to its low recoil.
Selection of Firearms for 5.7 and 9mm
In order to run the 5.7x28mm ammo, you should have either of the AR57, FN57, FN P90, ST Kinetics CPW, Ruger57, or XM17 Modular. These firearms have their chambers designed to hold the small grain 5.7. The Ruger-57 and the FN P90 are highly recommended because they are more popular.
The 9mm is old and can be called the jack of many trades. There are several arms with a 9mm chamber. They include; Beretta Cx4 storm, FMKs, Marlin Camp Carbine, Smith, and Wesson 1940, MGP SMG, TEC-9, Brugger and Thomet VP9, and Glocks.
9mm and 5.7 Costs
The 9mm easily wins our favor in this category as it is generally cheaper than the 5.7mm. This is the case regardless if you get in a brass or a steel case. The 9mm is also a lot more economical because of the volume of ammunition it has compared to the 5.7mm.
The 9mm is a simple round. It is also among the fastest-selling handgun rounds today. So, you can get it from almost every gun shop. Another advantage of the 9mm is that it’s easy to reload.
The 5.7 is banned for self-defense in some parts of America due to its armor-piercing ability. It is not as available as the 9mm due to its price and limited.
The 5.7 does not have parent casings. The cartridge was built anew. However, since the cartridge is not as common, it doesn’t attract enough patronage as the 9mm.
The 9mm offers an excellent load offer. The ammo can be fired with several arms, which has attracted a constant stream of new and exciting loads developed globally for the 9mm.
Reloading of 9mm and 5.7
It is a lot easier to reload the 9mm than the 5.7. However, you will be spending much more than you would in buying a box of readymade cartridges.
The 5.7 is complex, and it is relatively costly to manufacture. The round is difficult to reload.
The 5.7 was recorded at a velocity of 1740 fps when fired with a Ruger-57. When the 9mm was fired with a Glock19, it clocked a speed of 1,360fps. This velocity may vary by round type.
5.7 and 9mm Magazine Capacity
The smaller case diameter of the 5.7x28mm gives it an incredible magazine stacking capacity. Loading in an FN five-seven standard magazine, the mag could contain as many as 31 rounds of the 5.7.
The 9mm is more prominent than the 5.7, and for this reason, it cannot stack as much as the 5.7 does. The stacking capacity of any magazine depends on the gun model and type.
Soft Body Armor Penetration
The 5.7 was initially designed to defeat Soviet body armor. It was able to pierce through a Level 3A soft body armor. Although some unique 9mm custom build would do an excellent job at piercing the same armor, not all have such capability.
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5.7 and 9mm Ballistics Comparison
The ballistic performance statistics between the 5.7 and the 9mm is another contrastive feature to be considered.
The 5.7x28mm packed punch energy of 394ft-lbf when recorded at a speed of 716mps.
A Winchester 9mm packed punch energy of 455ft-lbf when recorded at a speed of 407mps.
Overall Winner: 9mm
Even though the 5.7 is a great cartridge to get the job done quickly in both combat and self-defense situations, the 9mm is a better choice for home and personal defense. It is cheap and available with good ballistics. Moreover, the 9mm is not banned in any country where arms and ammunition are not.