Avoiding hearing damage with (less) powerful rifles.

[Pinkbunny]

Hello again. Sorry about the thread I started on new vs older hunting rifles, I am sorry if it caused some discord on the site.

I was reading the stickied thread, "Avoiding hearing damage with powerful rifles," and I am glad to hear I should double my protection. I've always used either muffs or plugs, not both.

However, doing some research:
I'm going to assume that the most common rifles people will be shooting(on average) are going to be .308(plentiful, once this silliness is over, surplus ammo), 30-06(until a few months ago, plentiful surplus ammo, still, I think, the most common hunting round in the US), or 7.62x54(people love their Mosin's). The DB ratings I could find(http://www.freehearingtest.com/hia_gunfirenoise.shtml):
.308 in 24" barrel 156.2dB
.30-06 in 24" barrel 158.5dB
.30-06 in 18 _" barrel 163.2dB

I don't know if these are the reported db at the muzzle, or near the buttstock, so take those numbers how you will.

According to this chart(http://www.noisehelp.com/noise-dose.html), more than one hour's time spent hearing decibel's in excess of 94 will cause hearing loss. Now, I am assuming that every single second is not spent hearing high decibel sounds. Let us assume that we are hearing, overall, 10 minutes worth of high decibel noise over the course of, say, 1-3 hours at the range, from your own shots, and those near you. This would likely go up greatly in a crowded indoor range. That would be around 102 decibels.
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Now, I am leaning in two directions, and I am sure most people have the same problem:
1. Maximum protection
2. Ability to hear ambient noises(say, below 87db, as 90 is considered dangerous), for example, friends, range officer, or if you are getting firearms training, or even hunting.
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The molded ear plugs are nice, I don't know about you, maybe I'm doing it wrong, but I always have trouble putting in, and keeping in, the disposable foam plugs. However, according to this(http://www.earplugstore.com/gennoisprot1.html) the hearing protection provided by foam earplugs is by far greater than that of molded ear plugs.

Even the best ones, I have read a good bit about Ear Inc's, are less. The best foam have a noise reduction rating(nrr) of about 33. Ear Inc's Chameleon Acoustic filtered, which have the ability to let you hear ambient noise, don't list their nrr(http://www.earinc.com/p1-filtered-afiltered.php), but their non filtered model(http://www.earinc.com/p1-nonelectronic-instamold-rec.php) is 29.8. I'm not a math whiz, but I do know that decibels are on a logarithmic scale, so the difference is huge, between 33 and 29.8, right? Also, I would assume the filtered ones would have a lower nrr.
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On to muff's, what I hear is the gold standard among electronic ear muffs are the Peltor Tactical Pro(http://www.amazon.com/Peltor-MT15H7F-SV-Tactical-Protector/dp/B0006968YM), which have a nrr of 26. The much less expensive passive ones(http://www.amazon.com/3M-Peltor-H10...UTF8&qid=1361234461&sr=1-1&keywords=ear+muffs) have a NRR of 30.
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Is there any number whiz out there that can determine what the nrr rating would be for using two devices? I know they wouldn't just add on to one another. How does one calculate that?

And does nrr just subtract from the db given(unlikely), or is that another calculation?

Is it safe, long term, to use molded, filtered plugs and electronic muffs, or should one stick with the more deadening passive muffs and foam plugs?

Are you still going to get hearing loss, regardless?

Sorry if this seems stupid. I have been a recreational shooter, only rarely shooting. I wanted to take this more seriously(picked a bad couple of months to decide that ), and wanted to know the best course.

Edit:
Also, in the stickied thread, hearing loss via bone conduction through the buttstock was mentioned. Is this an issue? Also mentioned were there were things that could mitigate that, but not what those are. Any idea's?
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Edit 2:
I'm sorry if this seems really complicated, I'm just trying to get all the information out there.
My basic question is:
Is a plug and muff "good enough" protection, or will it just lessen the hearing damage? And if it is "good enough," is it just the maximum(foam plugs/passive muffs) that is good enough, or are filtered plugs/electronic muffs(to allow you to hear conversation) safe to use?

 

[CGT80]

I have heard that foam plugs (33 db) plus ear muffs only equal out to 36 db or so. I use custom molded plugs with baffles and electronic muffs. This works pretty well for pistol use. I have to turn the volume up all the way on the muffs. This seems to block the sound better than just muffs or just plugs. Race guns can be very loud, so having to RO them changed my habits.

For rifles and my shotgun, I wear foam plugs and electronic muffs. It is a bit harder to have a conversation, but still doable. When shouldering a gun, the muffs can be tweaked enough to break the seal, so the foam is for insurance.

When I shoot mid to hot loads in my 460 revolver, I use 33db foam and 31db passive muffs. The sound from that thing is incredible, not to mention the concussion from it.

I tried the electronic ears without plugs but it seemed like the seal wasn't the greatest on them (Pro Ears Pro Tac Gold). It was also hard to find a good volume. The knobs are infinite and easy to bump. A clicking knob would be better, then I could choose a certain number of clicks and keep it there.

The Pro Ears muffs have good electronics. They do not cut out all sound when a gun goes off. They just reduce the volume of the sound. You can carry on a conversation next to someone who is shooting, without every other word being cut out. The cheap muffs just shut off the sound when it exceeds a certain volume.

I have heard of sound conducting through bone also. That is one reason to wear muffs vs. plugs.

Wish I had more answers for you.

 

[chris in va]

Keep in mind, that 160 decibels is measured in miliseconds, not constant.

 

[Zak Smith]

I'm going to assume that the most common rifles people will be shooting(on average) are going to be .308(plentiful, once this silliness is over, surplus ammo), 30-06(until a few months ago, plentiful surplus ammo, still, I think, the most common hunting round in the US), or 7.62x54(people love their Mosin's). The DB ratings I could find(http://www.freehearingtest.com/hia_gunfirenoise.shtml):
.308 in 24" barrel 156.2dB
.30-06 in 24" barrel 158.5dB
.30-06 in 18 _" barrel 163.2dB

FYI these numbers are not what we get using a calibrated B&K SLM at 1 meter from the muzzle. Most centerfire rifles similar to those listed meter 168-170+

 

[Pinkbunny]

So, the long and the short of it, is get good foam plugs, and get good passive earmuff's?

There will be hearing damage regardless, but it is all about minimizing it.

Then use filtered custom earplugs and electronic muff's if you are hunting, when you need to hear, and might have(among your buddies) 3 shot's expended all day(however, the nature of it, enclosed blind, or side by side shotgunning, will make the sound worse).

Is that about the long and short of it?

Thank y'all for y'all's replies, and I am sorry about the post seeming, well, overly complicated.

 

[Double Naught Spy]

FYI these numbers are not what we get using a calibrated B&K SLM at 1 meter from the muzzle. Most centerfire rifles similar to those listed meter 168-170+

You actually bring up a good point. Just what the sound pressure is isn't always correct for a variety of reasons. Sound pressure is definitely directional and positional. So depending where the pressure is measured will change the result. There will be a marked difference 1 meter in front of the muzzle than from 1/2 meter behind the muzzle in the "shadow zone" from the muzzle in the shooter's position. Both numbers will differ from positions half a meter or a meter to either side of the shooter.

Also, the amount of noise pressure will vary with things such as action type or barrel length, whether or not a muzzle brake is used, etc.

In reality, it isn't the pressure being produced by the gun that is at issue (although it is the culprit and relevant) so much as the pressure actually getting to the person(s) being affected.

Being behind a Barrett M82A1 with doubled up protection isn't too bad. Spotting from directly behind the shooter isn't too bad. Being a meter either side of the shooter of a Barrett M82A1 with doubled up protection can be downright unpleasant.

 

[Pinkbunny]

You actually bring up a good point. Just what the sound pressure is isn't always correct for a variety of reasons. Sound pressure is definitely directional and positional. So depending where the pressure is measured will change the result. There will be a marked difference 1 meter in front of the muzzle than from 1/2 meter behind the muzzle in the "shadow zone" from the muzzle in the shooter's position. Both numbers will differ from positions half a meter or a meter to either side of the shooter.

Also, the amount of noise pressure will vary with things such as action type or barrel length, whether or not a muzzle brake is used, etc.

In reality, it isn't the pressure being produced by the gun that is at issue (although it is the culprit and relevant) so much as the pressure actually getting to the person(s) being affected.

Being behind a Barrett M82A1 with doubled up protection isn't too bad. Spotting from directly behind the shooter isn't too bad. Being a meter either side of the shooter of a Barrett M82A1 with doubled up protection can be downright unpleasant.

On that note, I found this guy while researching: http://michiganaudiologycoalition.o...sentation-upload/MAC-2012-10-23 PDF-final.pdf

They did tests, showing db exposure in enclosed hunting blinds, in a room, shooting side by side(like bird hunting), and standing to the side of a shooter. The exposure was very great to someone standing to the side of the rifle, like a trainer or range officer.
Edit: That part start's 77 pages in, if you want to check.
Edit2: Another nugget worth knowing. The "54 gun salute's" safe distance away, where noises are below 85 db, is 6 meters(20 feet). So, if you are 20 feet away from someone firing a gun outside, you don't need to put on your hearing protection yet. Of course, this doesn't count on places like concrete, or across a pond.

 

[redneck2]

Did you read the stickie at the top of this forum??

 

[Pinkbunny]

Of course I did. That's why the title seems to be a exact copy of the stickied thread.

If you had bothered to read the post, rather than trying to sound smart, you would have seen my reference to the thread.

However, dealing with hearing protection when you are shooting .50BMG is rare. This is about the more common, lesser decibel caliber's, that are fired a lot more at a time.

Edit:
Made up number time
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A .50, which is what the stickied thread is about, goes for what? $5 per round? Maybe you shoot that 5 times in the course of a day.
A .223, or 7.62x39, or .308, or 30-06, which many people likely have hundreds, or thousands of rounds of, might be fired 100 times in a single day at the range.

Even if the db's are much less for those, as opposed to 50, it's a completely different problem, with the *amount* of shots.