Silenced weapons can get incredibly silent. But, mostly not quite enough to prevent anyone from hearing it for a city block. For comparison, the modern handgun produces 156 to 168 dB when firing without a suppressor, and 117 to 140 dB when firing with one fitted. The bigger the caliber, the louder the sound emitted when It is fired.
There are a lot of solutions at the market for silencing weapons but, a general rule of the thumb is that the larger the cartridge you fire, the louder the gun and thus, the louder the gun when suppressed. This is due to the fundamentals of a firearm, which is basically the combustion of gunpowder that produces a gas that drives a bullet down a barrel that is barely larger than Its diameter.
How does suppressor work?
How efficient suppressor will also depend on the cartridge you use. Hence, the sound level of a suppressed gun is entirely dependant on Its caliber. This is why the most silent guns in the world are usually chambered in small calibers like .22lr for instance.
To understand how it works, you need to go back to the fundamentals of a firearm. Basically, it’s important to remember that the combustion of gunpowder that produces a gas that drives a bullet down a barrel that is barely larger than its diameter. And when the said bullet reaches the end of the barrel, guess what happens to the gas behind It?
That’s right, It escapes into the surrounding air. This is why there is smoke coming out of the barrel when a gun is fired. It’s like releasing a balloon full of air in an instant. The sudden release of the balloon’s gases causes a sound to be emitted.
And if you were to take a bigger balloon and release it, you would cause even more sound to be emitted because there is more air in the balloon. The same goes for guns. The bigger the caliber, the louder the sound emitted when It is fired. Hence, the sound level of a suppressed gun is entirely dependant on Its caliber.
Plus, there’s the fact that silencers only regulate the gases exiting the gun and don’t even tackle the other sounds emitted when a gun is fired, like the combustion of the powder and the sound of the bullet slicing through the air.
Again, the most silent guns in the world tackle these issues by firing subsonic rounds, which are rounds that have been purposefully loaded with lesser powder than usual to reduce the sound of the powder combusting.
They also tackle the issue of the bullet slicing through the air by firing cartridges with lower velocities, like the .22lr mentioned before. As you can see, guns that are truly effective with suppressors are purpose-built and thus, regular run of the mill guns firing regular ammo would still be loud with suppressors.
Such as the AR-15, which fires 5.56mm NATO and produces 167db of sound when unsuppressed and 136 dB of sound when suppressed, assuming It uses M193 5.56mm NATO.
Suppressors should be mandatory for self-defense in the home. Firing a gun inside an enclosure like your home will completely destroy your hearing. If not permanently for at least hours. It will also destroy the hearing of anyone else close by. It will likely be very painful with ears ringing loudly for some time. Even with a suppressed firearm, it will not be pleasant and possibly still painfull.
Being unable to hear in serious life-threatening situations increases the danger to you and all around you. Firing a rifle, even low power ones like a AR 15, a good choice for home defense, inside a home may be the last thing you will ever hear. A high power rifle like a 0.308, a very poor choice for home defense because of over-penetration, will likely burst your eardrums, like blood flowing out your ears if fired inside a house without suppression. Lite an old fashioned M80 firecracker off inside your home. That would be like a suppressed 0.308.
I have been at an outdoor gun range with a cover and forgot to put one ear protector back over one ear. I fired a 0.308 with a 30″ long barrel, no muzzle brake. Instant pain and ear ringing for hours. A shorter barreled 0.308 would be louder. One with a muzzle brake causes ear pain even with full ear protection on. A reason muzzle brakes are often banned in competitions. A 338 Lapua will cause pain with double ear protection if fired with a muzzle brake to the person standing next to the one firing the gun. That’s earplugs plus ear muffs.