Dry mini-can on 9mm carbine hearing safe?

[eldon519]

I'm not knowledgeable regarding suppressors, but I'm curious if it would be reasonable to achieve hearing-safe levels using a mini-can shot dry on a 9mm AR15? I think ideally I would use a 10.5" barrel because I like the carbine-length iron sights, but I don't want the upper to become too long and heavy.

I know most mini-cans are not hearing safe dry, but my carbine seems so much quieter than my Glock that I wondered if it might be possible on the longer barrel? Or would the bark just be redirected due to backpressure from the muzzle to the breech since it is blowback?

 

[Theohazard]

No silencer is truly "hearing safe" from a medical perspective. Repeated exposure to noises as low as 85 dB can cause hearing damage. Here's a good link from the American Hearing Research Foundation:

http://american-hearing.org/disorders/noise-induced-hearing-loss/

"Habitual exposure to noise above 85 dB will cause a gradual hearing loss in a significant number of individuals, and louder noises will accelerate this damage. [...] The highest permissible noise exposure for the unprotected ear is 115 dB for 15 minutes per day."

In contrast, the quietest .22 silencers on the market rarely get a shot down below 115 dB. Most pistol silencers are between 125 and 130 dB. Most rifle silencers are between 133 and 138 dB.

Now, it will probably take a heck of lot of shooting to get measurable hearing loss from shooting a suppressed .22, but considering the dB levels of a suppressed .22 with subsonic ammo are in the same range as a jackhammer, it's not truly "hearing safe". That said, I often don't wear hearing protection when I shoot my .22s and centerfire pistols outside suppressed with subsonic ammo. I figure the hearing loss I get is pretty small compared to the enjoyment of shooting without ears.

Silencers definitely make a huge difference, that's why I own three of them and I plan to buy more. But when manufacturers claim they're "hearing safe", that's incorrect and irresponsible. The industry bases their claims of a silencer being "hearing safe" on a misinterpretation of OSHA rules, and that claim is disingenuous at best.

 

[yugorpk]

The OSHA standard does not take into account milliseconds of 100+ dB exposure and should be considered irrelevant for silencer design and the sound exposure of silenced firearms.

 

[jmorris]

No silencer is truly "hearing safe" from a medical perspective. Repeated exposure to noises as low as 85 dB can cause hearing damage.

Depends on the source but even the most conservative would say at 85 db your shot would have to make that sound level for 8 hours, not a millisecond.
http://www.gcaudio.com/resources/howtos/loudness.html

Here are two "real world" videos.

If you can stand the sound of a dry fire this one would be safe. Video shows that it is even quieter than a "suppressed" air rifle.

https://www.youtube.com/watch?v=srXMYpYFZ8c

This is one of my suppressed 9mm AR's, note that the bullet impacting on the steel plate 100 yards away makes more noise than the rifle.

 

[Theohazard]

If you can stand the sound of a dry fire this one would be safe.

No, that one is not hearing safe either. I've never heard of a 9mm silencer can regularly get the average dBs down below 125 dB with standard subsonic ammo. 125 dB is well above the threshold for permanent hearing loss from repeated exposure.

 

[jmorris]

You obviously didn't watch the video. Go back and give it a look, your quote was "no silencer", why the first video is of a suppressed air rifle and a .22 LR.

My 3 year old girl farts louder that the sound the rifle makes firing.

https://www.youtube.com/watch?v=srXMYpYFZ8c

 

[jmorris]

Here is another video of the 9mm AR shooting steal at 60 yds. The noise of the cars driving down the road are 1/4 mile away. I won't argue db levels because I have never measured it but I don't ever feel the need to plug with it.

 

[Theohazard]

Depends on the source but even the most conservative would say at 85 db your shot would have to make that sound level for 8 hours, not a millisecond.

Yes, but no silencer can get a gunshot down anywhere close to 85 dB. The myth of the Delisle Carbine being that quiet was just due to inferior 1940s testing equipment; modern tests show it metering around 128 dB.

You obviously didn't watch the video. Go back and give it a look, your quote was "no silencer", why the first video is of a suppressed air rifle and a .22 LR.

Your quote was regarding a suppressed 9mm, so that's what I responded to. But now that I watched the video, my quote still stands: That suppressed .22 is about as loud as a jackhammer as far as decibels go, no matter what your ears try to tell you.

I've never seen or heard of a production .22 silencer that regularly gets the sound down below 110 dB from a rifle with standard subsonic ammo (and usually it's more in the 115 dB range for the best ones). 110 dB is about the same as a jet takeoff if you're standing a few hundred feet away. Sure, a suppressed .22 doesn't actually sound anywhere near that loud to the human ear, but that's because the duration is so short. Also, when we shoot suppressed we're often mentally comparing it to what it sounds unsuppressed, and the comparison is so huge that we fool ourselves into thinking the shot is quiter than it really is.



Now, I'll bet it would take a heck of a lot of silenced .22 shooting to get noticable hearing loss, and there are probably plenty of other things we do in our daily lives that can cause more hearing damage than that. And I'll also admit that I don't generally use ear pro when I shoot my .22s or my centerfire pistols suppressed. But I'm also not going to perpetuate the myth that silencers are "hearing safe", because technically they're not.

My 3 year old girl farts louder that the sound the rifle makes firing.

If your 3-year-old has 115 dB farts, that's pretty impressive.

 

[eldon519]

For what it's worth, what I would really like to be able to do is simply shoot the gun on land with not-too-distant neighbors and have them not complain if I rattled off a couple hundred rounds in an hour. I was just using hearing-safe as a good benchmark for what I figured would be a feasible target. Of course it would be fantastic if it really were hearing safe, but I won't mind if I need to use plugs to be safe. Heck I still use muffs for my indoor pellet range just because it makes it easier for me to concentrate.

 

[yugorpk]

OSHA standards are valid for sustained noise and not milliseconds of noise. Its not something they address.

 

[jmorris]

No dB meter here, how about relative sounds?

If the rifle is not hearing safe I need to start plugging when I open a beer.

I live around 35 miles from the airport the jet in the background, of this video, landed at so it is likely around 10,000 feet away or more (was not watching exactly where it was at).
https://www.youtube.com/watch?v=x7ElKr7WzGQ

This article says a can opening makes 85 dB.

http://www.straightshooters.com/decibel-ranking-of-airguns.html

 

[Theohazard]

If the rifle is not hearing safe I need to start plugging when I open a beer. [...] This article says a can opening makes 85 dB.

First, nobody has said that you have to wear ear pro for 85 dB sounds. I'll quote the link in my first post again: "Habitual exposure to noise above 85 dB will cause a gradual hearing loss in a significant number of individuals, and louder noises will accelerate this damage." Notice the words "habitual" and "gradual".

Second, who said your suppressed .22 rifle was making 85 dB? Your suppressed rifle is probably 115 dB at best if you're using standard subsonic ammo, and that's 30 dB louder than opening a can of beer. And a 30 decibel difference roughly translates to about 8 times the loudness. So your suppressed .22 rifle has a decibel level that's about 8 times louder than a can of beer opening:

http://trace.wisc.edu/docs/2004-About-dB/

 

[Theohazard]

OSHA standards are valid for sustained noise and not milliseconds of noise. Its not something they address.

I agree. The links I posted specifically address one-time noise and constant noise, not staccato noises like gunfire. That said, they still give a good indication of the potential dangers of noise exposure. And at some point I'd like to contact an audiologist and see how those guidelines translate to an intermittent sound like gunfire.

The decibel level comparisons show that silenced firearms are a lot louder than many people think they are. Apparently jmorris has a distorted view of the actual decibel level of his suppressed .22 compared to other common sounds, and that seems to be common among many silencer owners.

 

[jmorris]

Apparently jmorris has a distorted view of the actual decibel level of his suppressed .22 compared to other common sounds

As I noted in #11 I have no dB meter so I don't have a distorted view of the actual level, I simply don't know what it is.

I figured everyone has heard a can opening and I can hear the can opening as the shot is being fired in the video I posted in #11 though. How much louder than the can opening do you think the shot is?

 

[Theohazard]

How much louder than the can opening do you thing the shot is?

I already told you that in post #12. It seems like I'm having to repeat myself a lot here, but I'll post this again: Your silenced .22 is probably metering about 115 dB at best if you're using standard subsonic .22 LR ammo (it's possible it could be metering closer to 110 dB, but that would mean all the conditions just happened to be perfect and you have one of the newer super-quiet cans like the Dead Air Mask). And 115 dB is in the same decibel range as a jackhammer:
[resize=700] [/resize]

You claimed that a beer can opening is 85 dB. That's a 30 dB difference. And since the loudness doubles about every 10 decibels, that means your suppressed .22 is about 8 times louder than a can opening.

I figured everyone has heard a can opening and I can hear the can opening as the shot is being fired in the video I posted in #11 though.

The audio in videos gives a terrible indication of how loud gunshots are, silenced or not. I've got videos of me rapid-firing an unsuppressed muzzle-braked AR, and the audio in the video makes it seem like it's not that loud. If you're trying to get an idea of how loud something is, using a video is not a good way to do it.

I have no dB meter so I don't have a distorted view of the actual level, I simply don't know what it is.

You obviously have a distorted view of the actual level. You're making the classic mistake of thinking your ears are somehow an accurate way to measure sounds, but they're not. That's why we use decibel meters to measure sounds instead of just guessing.

 

[jmorris]

that means your suppressed .22 is about 8 times louder than a can opening.

You obviously have a distorted view of the actual level.

If that is the case I would say your correct.

 

[Theohazard]

For what it's worth, what I would really like to be able to do is simply shoot the gun on land with not-too-distant neighbors and have them not complain if I rattled off a couple hundred rounds in an hour.

Mini cans like the Degroat Nano and the Thompson Poseidon tend to be quite a bit louder than regular pistol cans unless you shoot them wet. And when you do shoot them wet it tends to only last a few mags until they're dry again. Personally, I would never buy one unless I had the extra money and I needed it for a specific use that my Octane couldn't do as well, like a compact HD can or a can I could easily holster.

Also, keep in mind that the sound from a suppressed 9mm AR is a little different than a suppressed 9mm pistol. I haven't done any direct comparisons, but my impression is that the noise coming out of the action tends to be louder, and this seems to counteract the quieter effects of the longer barrel. This would make sense because it's a straight blowback action and not a locked-breech action like most pistols. Like I said, I didn't do any testing and I didn't compare them back-to-back, but a suppressed 9mm AR didn't seem any quieter to me than a suppressed pistol.

I would suggest a standard can like the Octane. That will definitely minimize any annoyance to your neighbors.

 

[wally]

I'm comfortable shooting subsonic 9mm loads suppressed without earpro. However, since we mostly shoot steel plates I still recommend earpro be worn as the ringing steel is still really loud at 10-15 yards distance. But everyone enjoys a few shots without it. At longer distances (25+ yards) or paper targets I'd be fine without earpro. YMMV.

OSHA types have floated the idea of restricting the SPL of music player "ear-buds" and rock concerts. No doubt a lot of old rock'n'rollers have damaged their hearing.