• Subsonic vs Supersonic Ammo: subsonic ammo is slower than the speed of sound, resulting in quieter gunshots; whereas, supersonic ammo travels faster than the speed of sound, creating a sonic boom.
  • Subsonic Ammo with Suppressors: For the quietest shooting experience, subsonic ammo is preferred with suppressors -- but it's not mandatory. Suppressors effectively reduce the noise from a gunshot but they can't eliminate the sonic boom of supersonic ammo.  
  • Advantages Subsonic and Supersonic Ammo: Subsonic ammo offers reduced noise, less recoil, and is safer for hearing. Supersonic ammo provides a flatter trajectory, greater range, and higher impact energy, more suited for long-range shooting and hunting. 
  • Popular Subsonic Cartridges: Cartridges like 9mm subsonic, 300 Blackout, 8.6 Blackout, and subsonic 22 ammo are well-known for their effective performance in suppressed firearms. 

Table of Contents

Subsonic Ammo vs Supersonic: Everything You Need to Know 

Shooting suppressed offers you a ton of benefits, including protecting your hearing, reducing recoil, and getting rid of muzzle blast, but what if those effects could be amplified?  

Subsonic ammunition has become very popular for its effectiveness at nearly eliminating sound and recoil when being shot suppressed.  

How does it stack up against traditional supersonic ammunition? 

We’ll look at both types of ammo, the advantages of each, and determine if subsonic ammo is more than just a party trick. 

What is Subsonic Ammo? 

Subsonic ammo is engineered to travel at speeds below the sound barrier.  

You may ask, what is subsonic speed? Subsonic speeds maintain a velocity under 1,125 fps to avoid the sonic boom, reducing the noise level of your gun shot.  

Subsonic bullets achieve this lower speed by using heavier projectiles and lower powder charges, which also aids in reducing recoil and flash.  

The elimination of the sonic boom allows your suppressors to shine. When paired with subsonic ammo silencers can be amazingly quiet, even more hearing safe, and the most fun you can have while shooting. 

And if you’re shooting subsonic 22 ammo? The sound of the bullet impacting the dirt berm was louder than the gunshot noise. 

Characteristics of Subsonic Ammo 

  • Speed: Remains below the speed of sound. 
  • Trajectory: Typically has a more curved trajectory due to lower velocity. 
  • Energy: Less kinetic energy compared to supersonic ammunition. 
  • Noise Level: Quieter than supersonic ammo, as it avoids the sonic boom. 
supersonic ammosupersonic ammo

What is Supersonic Ammo? 

Supersonic ammunition is designed to travel faster than the speed of sound, which is approximately 1,125 feet per second (fps) at sea level. 

When a bullet exceeds this speed, it creates a sonic boom, which you hear as a loud crack as the bullet breaks the sound barrier. This phenomenon significantly contributes to how loud a gunshot is.  

While silencers are excellent at reducing the sound of the combustion gases leaving your barrel, they cannot eliminate the sonic crack sound.  

Supersonic ammo is common in rifle and handgun ammunition, 5.56/223, .308, 6.5 Creedmoor, 5.7x28, and most 9mm rounds are all moving faster than the speed of sound. That speed creates a ton of energy upon impact, and these bullets experience slower bullet drop in-flight which makes getting hits at extended ranges much easier.  

Characteristics of Supersonic Ammo 

  • Speed: Travels faster than the speed of sound, greater than 1,125 FPS.  
  • Trajectory: Generally flatter trajectories due to high velocity. 
  • Energy: Higher kinetic energy upon impact. 
  • Noise Level: Creates a sonic boom in addition to the muzzle blast. 

Subsonic vs Supersonic Ammo 

The biggest difference in subsonic vs supersonic ammo is the speed the bullet is moving, either slower than or faster than the speed of sound. But that is not where the differences end. The bullet design varies greatly between the two types of ammo to maximize efficiency for the given speeds.  

Subsonic bullets tend to be heavier and longer. The longer length and extra mass means that these bullets can expand larger than supersonic bullets, which can make them very effective for certain hunting applications. The longer bullet also stabilize very well, especially with high twist rates as seen in 300BLK and 86BLK firearms. This makes the bullets incredibly accurate, while also being superbly quiet and low recoiling. 

Supersonic bullets are shorter and lighter than subsonics, allowing them to move faster. Supersonic rounds also use larger powder charges, which lets them reach speeds upwards of 3,000 FPS. The added powder and speed also mean that these bullets have better ballistic efficiency and flatter trajectory, allowing you to make hits at ranges beyond 300 yards much easier.  

Advantages of Subsonic Ammo 

Subsonic ammunition offers several benefits, particularly when used with suppressors: 

  • Reduced Noise: Ideal for stealthy shooting scenarios, like plinking at the range or hunting. 
  • Less Recoil: Super light recoil, softest shooting experience which improves accuracy. 
  • Hearing Safety: Safer for the shooter's and bystanders' hearing. 

Advantages of Supersonic Ammo 

Supersonic ammunition also has its own set of advantages: 

  • Greater Range: Higher velocity allows for longer-range shooting. 
  • Flat Trajectory: Aids in accuracy over longer distances. 
  • Higher Impact Energy: Highly effective for hunting and tactical applications. 

Popular Subsonic Cartridges 

Subsonic ammo has become increasingly popular over the last decade, as suppressors have become more common amongst 2A enthusiasts. We’ve seen the advent of dedicated subsonic rounds, such as 300 Blackout, 8.6 Blackout, and 375 Raptor, and rounds adapted to subsonic loads like .308 Winchester subsonics and 6.5 Creedmoor subsonic loads. Lastly, there are rounds that always had subsonci offerings, like .22lr, 9mm, and 45 ACP and now their potential has been fully unlocked with silencers becoming easier to get than ever.  

Several cartridges are popular in the subsonic ammunition category, known for their low noise and reduced recoil: 

300 Blackout Subsonic Ammo 

Designed by AAC to have super and subsonic loads, one of the first widely adopted subsonic rifle cartridges. This round uses heavy .308 diameter bullets, 190+ Grains, and low powder charges for amazing sound performance with minimal recoil. 

6.5 Creedmoor Subsonic Ammo 

6.5 Creedmoor is traditionally a very fast supersonic ammo, but is now being loaded in subsonic variants for ultra-quiet plinking when shooting suppressed. These subsonic loads are ideal in bolt action rifles where the sound performance can really shine.

308 Subsonic Ammo 

If you don't want to build a whole new rifle to shoot 300BLK, but you have a 308 Winchester in the safe, you’re in luck! You can now get subsonic 308 ammo, similar to 300 Blackout. You get all of the sound and recoil reduction, without having to get a new rifle.  

556 Subsonic Ammo 

5.56 subsonic ammo has become more popular recently, it generally uses heavy bullets, around 120 grains, paired with fast burning powders. These rounds are extremely quiet, but may not cycle in an AR15 rifle, they’re ideal for sue in suppressed bolt action riles. 

9mm Subsonic Ammo 

While most inexpensive 115 Grain 9mm training ammo is just over the sonic barrier, and moves around 1,200 FPS, there are tons of popular subsonic loads. Most subsonic 9mm ammo uses 124, 147, and higher grain bullets, and when paired with a suppressor have nearly no recoil and very minimal sound thanks to minute powder charges.  

22 Subsonic Ammo 

22LR subsonic ammo is commonly available, sometimes called “Standard Velocity.” This ammo is popular for plinking, competition shooting, small game hunting, and just having fun shooting suppressed. We have found the quietest subsonic 22 ammo to be CCI Quiet and CCI Standard Velocity.  

8.6 Blackout Subsonic Ammo

300BLK’s big brother 8.6 BLK is a newer cartridge designed for both super and subsonic performance. It uses .338 diameter bullets and 1 : 3 twist barrels to maximize energy on target, and is rated for hunting large game animals. It is excellent when paired with a suppressor for mild recoil.  

375 Raptor Subsonic Ammo

Similar to the Blackout cartridges, the 375 Raptor can be fired supersonic or subsonic, and uses high mass bullets, perfect for quiet shooting and hunting. The 375 Raptor slings 400+ Grain bullets at 1000 FPS, with very minimal recoil, flash, and sound.  

.45 ACP Subsonic Ammo

Not only is the 45 ACP the back-to-back World War champion, it is naturally subsonic which makes it an awesome round to shoot silenced. 45 has a low case capacity and shoots 200+ grain bullets, giving it great ballistics with nearly no recoil when shot with a good silencer.

popular subsonic cartridgespopular subsonic cartridges

Can You Shoot Subsonic Ammo Without a Suppressor? 

Silencer will work great with either type of ammo and will still reduce the sound levels to a much more comfortable volume, regardless of if you’re shooting subsonic or supersonic bullets.  

Silencers are great for trapping the muzzle blast and quieting that down, but thanks to the laws of physics they can’t get rid of the crack of the sonic barrier. Luckily, subsonic ammo doesn’t break the sonic barrier, so silencers reach their maximum efficacy.  

Key Points 

  • Suppressors and Subsonic Ammo: More effective noise reduction as both muzzle blast and sonic boom are minimized.  
  • Suppressors and Supersonic Ammo: Reduces muzzle blast but not the sonic boom. 

Why do People Shoot Subsonic Rounds?  

People see lower velocities, less energy, and question, why are subsonic bullets better? There are a few great reasons to use subsonic ammo compared to supersonics. We have already covered the massive difference in sound performance between subs and supers, but let’s look at a few other key uses. 

Practice and training 

Subsonic ammo also creates substantially lower recoil, making it excellent to learn the fundamentals of marksmanship.  

Less sound, less recoil, and less blast result in shooters not flinching while shooting. The shooter can focus on things like grip and consistent trigger pulls when they’re not fighting against the sound and recoil of the firearm. 

Accuracy 

Most ammo is destabilized when it slows down and goes “transonic” or goes from supersonic to subsonic. This destabilization makes the bullet veer off course, often resulting in a miss. Subsonic ammo remedies that by never getting into the transonic zone, allowing to stay stable through its entire trajectory. 

This makes it great for certain long-range shooting, like .22lr precision rifle matches where subsonic ammo is preferred by shooters. 

There have even been hits out to 1000 yards with subsonic 300BLK, as demonstrated by Alabama Arsenal shooting the Q Mini Fix 

Competition 

Subsonic ammo is the go-to option for USPSA competition pistol shooters. 

Grand Master shooter Hunter Constantine noted “Heavier rounds recoil less, allows me to shoot faster and more accurately when competing.” 

Subsonic rounds are also preferred by 22NRL shooters, for their consistency at extended ranges. 

Hunting with Subsonic Ammunition 

Because subsonic rounds have lower speed, they work a little differently than supersonic bullets in hunting applications. Usually, these rounds use expanding projectiles to create effective hits on game animals. 300BLK, 86BLK, and 375 Raptor are all examples of subsonic hunting bullets that are effective on most animals in North America.  

Some tried and true 300 blackout subsonic hunting ammo is Hornady’s 190 SUB-X load, it is incredibly accurate and is effective on small and medium sized animals, like feral hogs. We’ve also use the 190 Sub-X bullet in handloaded 308 subsonic ammo for hunting with good results!  

Paired with a suppressor, these bullets achieve “Hollywood quiet” status, they’re incredibly quiet and make hunting even more enjoyable. We have seen many instances where we could take a shot on our desired target without disturbing the rest of the herd, which meant we got multiple hogs instead of just one. The best part is not having to wear hot, bulky hearing protection while enjoying the outdoors. 

Subsonic Ammo FAQs 

What is subsonic speed? 

Subsonic refers to speeds under 1,125 feet per second, or any speed under the supersonic sound barrier. 

Is subsonic ammo better than supersonic? 

Subsonic ammo has less sound, flash, and recoil compared to supersonic ammunition. One is not better than the other, they are different tools for different jobs. 

 Why would you want a subsonic bullet? 

Subsonic ammo is preferred when sound and recoil are a priority, these bullets can also be effective in hunting and rimfire long range shooting scenarios.  

Is subsonic ammo really quieter? 

Yes. Subsonic ammo is significantly more quiet than supersonic ammo due to not creating a sonic boom when being fired. This advantage is amplified when being shot suppressed.  

Conclusion 

The choice between supersonic and subsonic ammunition depends on the shooter's needs and the specific scenario. Supersonic ammo is suitable for long-range shooting where noise is not a primary concern. In contrast, subsonic ammunition, especially when paired with a suppressor, is ideal for situations where noise reduction is crucial. Understanding these differences helps shooters make informed decisions to best suit their shooting style and requirements.