Subsonic ammunition is more and more in demand these days, but there is still a lot of confusion about it. The good news is that the whole thing is much less complicated than it seems. Once you have understood the basics, you can easily get the right round for your purpose.

1. What Makes Ammo Subsonic?x

Simply put, ammunition is subsonic if its projectile is propelled at a velocity that is slow enough that it does not break the sound barrier. This would be velocities a little under 1100 fps (feet per second). The exact velocity depends on the atmospheric conditions and can change.

If a projectile moves at velocities faster than that of the sound, you will hear a sonic boom in the form of a high-pitched crack along the trajectory. Staying below the speed of sound, you avoid this noise.

2. Why Should You Use Subsonic Ammo for Suppressors?

The obvious reason is that you use a suppressor to reduce the noise of the shot itself. Reducing it further by eliminating the supersonic loud crack of the rounds flying after they left the barrel makes just sense.

If you do not use a suppressor, you will most probably not hear the difference as your gun will be loud enough. However, once you reduce that sound enough with a can, you will appreciate the sonic crack to disappear as well.

The suppressor itself cannot influence the noise of the projectile in flight. It just contains the muzzle blast and slows the expanding gasses down while redirecting them. The bullet, however, is on its own. Making it subsonic completely eliminates its noise.

Don’t get me wrong. Your gun will not be completely silent, but the noise level will be extremely reduced. You will hear the action and the impact of the bullet while saving yourself and your ears a lot of stress.

3. Why Does Everyone Want Subsonic Ammo Nowadays?

Today, more and more shooters take to using suppressors. However, these reduce only the noise of the shot, not the sound of the bullet breaking the sound barrier. For that reason, in order to lower the noise level even further, subsonic ammunition is used for a suppressed gun to make it extremely quiet.

Also, without the sound, subsonic ammo and suppressed guns are much more comfortable to shoot. Often enough, these subsonic loads have less recoil, making it even more fun. At the same time, they are still quite useful when it comes to self-defense and hunting.

In fact, a lot of the old cartridges are completely subsonic at standard loads. Some of them, like the .45 ACP, are still in use today. However, with new technologies, other old and slow cartridges are now regarded as obsolete. When it comes to handguns, many production loads are subsonic. This is especially true when you look for heavier for caliber bullet weights. In such a case, you need to check also if your gun stabilizes them sufficiently before you use them.

4. When Should You Not Choose Subsonic Ammo?

Using subsonic ammo does come with some limitations. Especially when you are new to this, you have a few things to consider. This starts already with the selection of your gun and suppressor. The cartridges come last.

First and foremost, you have to make sure that your gun can stabilize the subsonic bullets. Usually, these are heavier which makes the right twist rate very important. Otherwise, you risk a baffle strike which can cause serious injury and quite some damage. Shoot the rounds without your can through paper. That is the easiest way to see if they are stabilized properly.

When it comes to the suppressor itself, most common are over-bored ones. That would be a suppressor made for .308 used on a .223. This way, they do a good job with supersonic loads that generate enough gas pressure. If the round is underpowered, it might not pressurize an over-bored suppressor enough. The result is that it is actually louder at the muzzle.

Another problem is the use of a semi-automatic gun. Often, subsonic cartridges are not powerful enough to cycle them reliable. This makes bolt action rifle preferable. Using an AR10 for a .308 load, you might have to cycle the action manually after each shot.

5. Which Guns Are Great for Shooting Subsonics?x

First of course, you need a gun with a threaded barrel. If you really want to shoot subsonic and they have the priority, you need to take something with the right action and chambering. A .223 or 5.56 AR is actually very good for using a suppressor, but very bad for shooting subsonics. You would use too much performance with these rounds.

While a rifle in .300 Blackout is a great idea, you should go for a bolt or lever action gun if you want it to be even quieter. A semi-auto will leak gases, so you might end up with a single-shot weapon.

For handguns, single-shots and semi-autos are the way to go. Revolvers have a gap between the cylinder and forcing cone so that they do not work well with a suppressor.

For any gun, check the twist rate if it really stabilizes the bullets you want to use. Verify it with a few groups on paper.

6. Which Subsonic Cartridges Are Good?

If you are just finding your way into subsonic shooting just now, you better start with some of the ideal cartridges, as they make your life so much easier. As a general rule, think of heavy bullets and small cases. One good example is the .300 Blackout. This is designed to work both with subsonic and supersonic loads. This means that your rifle will have no problem feeding both. Only minimal adjustments might be necessary here or there.

Looking at the 7.62×39 mm, this is another cartridge that can easily be made subsonic, but be careful with factory loads which are typically supersonic. If you want to go hunting, choose the .450 Bushmaster, .458 SOCOM, and .45-70. Another good cartridge is the rather new .350 Legend.

If you want to choose your handgun subsonic, use either .45 ACP or 9mm. While .45 ACP is normally subsonic, for 9mm, you have to take loads with a 147-grain bullet.

7. Which Cartridges Are Not So Good for Shooting Subsonic?

Every cartridge that typically propels its bullets at very high velocity or comes with a high case capacity is a poor choice. A good example is .223. While its case does not have a very big capacity and can be loaded down for subsonic bullets, you also cut down its performance. You end up with the equivalent of a .22 Magnum. For your AR15, that would mean that it could not cycle the action.

6.5 Creedmoor is another poor choice. While you can also load it to subsonic levels, you still have a light bullet that does you not much good. The big bullets of the .338 Lapua on the other hand look promising, but this round comes with a big case capacity. In other words, you end up with an oversized round. The same holds true for the .300 Magnums.

8. Subsonic Factory Loads

The range of available subsonic factory ammo as increased dramatically over the last few years. They can be used for target shooting, hunting, and self-defense. Also, there are cartridges designed to be subsonic. Here, .300 Blackout is one of the best choices as it brings you the best variety. There are also loads like Hornady`s 410-grain Sub-X in .45-70 and Winchesters 265-grain Super Suppressed .350 Legend. There are also factory loads for .22LR (22 Long Rifle) that are worth considering. They come with the added advantage of being widely available and cheap to buy.

9. How to Handload Subsonics?

Handloading subsonic rounds is much older than the hype. Many shooters have created their own loads, and there is a lot of data available. If you already have the equipment available, this is a good idea to use it for subsonics as well.

Best is to handload for lever and bolt actions. They are easy as you cycle their action anyway for each shot. If you use high volume to weight powder, like Trail Boss, you will get the consistency necessary as you use up enough space inside the case.

You might need some special load manuals that include subsonic loads. Otherwise, you can work on it yourself. Here it is better to start too low and to slowly, step by step, work your way up.

10. Hunting with Subsonic Ammo

Subsonic cartridges can be used for hunting without a problem, but they are not necessarily the best choice. They have their limitation producing less damage and might not expand as they are supposed to. Finally, less speed and heavier bullets make for trajectory with a lot of drops so that they are rather for shorter distances.

There you have it guys, the most important things you need to know before going subsonic. If you have some ideas or experience to add, please share them with all in the comments.

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