The 48dB recorded will also include back ground level noise.
Cheers
Pete
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Do you guys notice a difference between dry and wet surrounding bush / grass? It seems to get louder if it has just rained imo....
Iv seen that with reds and bare muzzel 303s on more than one occasion. Taking out the lead hind is the best way to make it happen. Having shot with both supressed and non suppressed over the years I cant say Iv seen a significant difference. Sometimes they run sometimes they dont. A while a go we shot 2 stags with a braked 280ai and a clean 7mm08, a third stag just stood looking at us while we discussed how much we already had to carry out.maybe a couple of minutes before it left the scene.
They way I use them is the noise reduction when shooting around stock, couldn't use my rifle without, the Bulls would stampede!
Main reason I got suppressors is to protect my hearing and those around me. I'm not too worried about 450m away.
The stock where this test was carried out (bulls about 30 metres away, horses 150m or so, dogs 250m) never seem to mind the shooting - suppressed or otherwise!
To state the obvious - most people fit a suppressor to larger calibre weapons to reduce the recoil, the reduction in noise at the point of firing in a bonus factor. Suppressors fitted to small calibre weapons are for the noise factor (muzzle blast) noting that - as pointed out by Mat2308 - the suppressor will have no effect on the sonic noise created by the projectile.
I have Tinnitus from helping a neighbour to build a fence. Wish Paslode made suppressors for their nail guns
ok seems my last post disappeared into nothingness ( no bad language etc so who knows)
dB is a log scale invented by alexander graham bell's company to pretty much talk about volume on phone lines. however a "bell unit" was way to loud so in came the decibel (1/10th of a bell). ok here it gets slightly techy.
to increase sound pressure (what you hear) increase by 10dB, to decrease what you hear by 1/2 decrease by 10dB
now subsonic loads have no penetration into the supersonic so as they silence only the muzzle "crack" the projectile itself is relatively silent. above the sound of sound although you may silence the muzzle blast the projectile will still make a supersonic wave to hear.
so to give an example a 38 revolver is 138dB, about as loud as a 747 plane at take off, but 128 dB is 1/2 as loud. 118 dB is 1/2 as loud as that again.
it also works the other way add 10dB and its what you perceive as twice as loud, still mazes me that salesmen keep telling me that double the amplifier power = double the volume. well thats what you get when you pay peanuts.
any more question feel free to pm
For obvious reasons hunters rarely use hearing protection when they hunt. Unfortunately unsuppressed gunfire from hunting rifles is loud enough to cause permanent hearing loss.
An unsuppressed rifle produces noise levels of 165 -170db and those with silencers should reduce it by about 20-30db.
How about a simple test?
We invite all the brands to test the silencers and muzzle brakes (for recoil) on 1 day. We test the following
Brand
Weight
Length
Diameter
db no silencer (The sound meter must be at the back where your head would be if fire a rifle)
db with silencer
Chrono without
Chrono with
Barrel temp with
Barrel temp without
Silencer start temp
Silencer end temp
Recoil with
Recoil without
We test it with 2 rifles a 243 and a 300wm
sounds good...might be hard to get all suppressors fitted to 2 rifles though. easy to do a 'bring what you have' and test them with and without suppressor on.
Decent testing equipment isn't cheap and cheap gear doesn't accurately measure levels.
A discussion on the other forum got petty and personal when a number of suppressor makers joined the arguments.
I'm afraid you're comparing apples with elephants there.
A revolver may have a -peak- noise level of 138dBSPL but a large jet engine is producing -continuous- noise of that general level. The mechanism of damage with firearms is very different to continuous industrial noise. The former causes instantaneous structural damage to the Organ of Corti while the latter is largely a fatiguing mechanism that leads to outer hair cell loss initially, and more diffuse damage later as things worsen.
Current occupational guidelines prohibit exposure to any continuous noise exceeding 115dB(A) and any impulse noise exceeding 140dBSPL is considered dangerous.
Can I suggest people refrain from "clarifying" technical aspects by reading basic references. It really adds nothing.
6x47 (Clinical Audiologist)
@stevodog, The only way to do this legit is to use the same gun with the same ammo. The silencer suppliers just have to provide the same thread silencer for that caliber. This is the only way to have a fair test. @dogmatix, I'm sure we can sort that out without buying a unit @bully, The majority hunters don’t use them or haven’t got earmuffs.
Are you going to provide the guns and the ammo, knowing that there are about a dozen brands represented on the NZ market and some with two or three models for one brand ? As to the muzzle brake, some require indexing to properly work...another little head hack .
Who is supplying the proper expensive testing equipment?
i can provide a .243, if you want to back your brand you will be there.
the guys doing the crazy car sound could do it again
I think we are missing a key point or two. And its again comparing apples with oranges if we focus purely on sound reduction.
Most customers in NZ are buying a suppressor that is a compromise, a balance between weight, sound suppression and cost.
Whether this is for hunting the hills with a bolt action or shooting a semi, usually for more rapid fire usage, ie targets or pest control.
I used to have two Reflex T8 cans, awesome 1990s technology designed for full auto use in the military.
Those things will never fail, could handle extreme rates of fire and temperature and were pretty good for sound reduction even compared to modern designs.
Would I use them for lugging around the hills in NZ again? No ffffing way!
I changed and went for DPT modular for my hunting rifles. For that purpose their light weight, low cost and pretty good sound reduction is hard to beat.
Even if they don't have the longevity of steel designs (although the new steel baffle insert is the solution in my opinion).
For a semi auto application, I would look elsewhere, for moderate cost and excellent sound reduction, but heavy weight is something like a ASE.
There are cheaper options as well, but again they aren't light. You would need that high spec testing equipment to separate these out.
There are also other design factors, such as internal muzzle brake and back gas design, again these things will costs more.
If you have the $ and want the best of everything, then you could go titanium, with ODL.
So testing purely on sound reduction is a bit pointless in my mind, as you need to give equal weighting to cost, weight and intended usage.
And the LEM by MAe that came on my latest purchase weighs more than one of the alloy heads on my car. But I expect no one will ever hear the gun go off or hope so cos you won't carry it too far that's for sure.
Attachment 47897:XD:
This isn't an unknown, there are tons of threads on here and on Fishnhunt doing backyard tests on suppressors with substandard sound equipment and even relying on old human ear drum Mk101, sorry Possumtrapper :D, as well as some good comparisons.
http://www.fishnhunt.co.nz/forum/YaB...1402472871/0#0
http://www.fishnhunt.co.nz/forum/YaB...1406260467/0#0
http://www.fishnhunt.co.nz/forum/YaB...1459450986/0#0
http://www.fishnhunt.co.nz/forum/YaB...1443598908/0#0
http://www.fishnhunt.co.nz/forum/YaB...1435475519/0#0
http://www.fishnhunt.co.nz/forum/YaB...1440616677/0#0
http://www.fishnhunt.co.nz/forum/YaB...1431327925/0#0
You can also check each manufacturer's website for their own testing results.
Without the very expensive equipment (most cheap stuff is only good for measuring continuous noise, not peak impulse noise) and a full range of equivalent suppressors (graded by cost, weight, material etc) in the same calibre and correct thread, its going to be hard to get a definitive answer.
Another key assessment should also be customer satisfaction, as there will always be some makers who go the extra mile and some who are lacking in customer services skills.
I previously mentioned that a suppressor thread on Fishnhunt ended up as a bitch and squabble between supporters and indeed suppressor makers, so I'll be pleasantly surprised if you can get the various NZ (and overseas - ASE are an active forum member) makers to want to be involved, as they won't want their products looking bad.
I do agree, having one set of testing under the same conditions would be good, so best of luck.
Well 6x47, I for one would like a bit of input from an audiologist and I imagine most other would as well.
For more info than anyone would like to know about "doubling sound". This link will help. This goes into the necessary inputs of sound duration and other factors that contribute to subjective sound levels.
For a guide on higher level peak sound this PDF is very useful. NIOSH/Criteria for a Recommended Standard--Occupational Noise Exposure, 1998
I took the dBA dose percentage and calculated the number of shots each level would allow before breaking the "8 hour threshold". Shot impulses are in microseconds so even a small time fram seems to allow for several shots over 8 hours in a day at 140 or less.
I would like to get a professional view on whether this method is correct or even opinions on this, 6x47. The reality in hunting is that most people will not wear ear muffs and most will not shoot their rifle remotely from 450 meters. Subsequently some guide on the sound levels that are acceptable would be good. I know for a fact that suppressors can reduce sound at the ear better than some single ear protection setups with braked rifles.
Regarding recoil. Brakes inside a can cease being a brake once they are inside the can. I am producing my first Ratchet Locking can over a brake or flash hider now. When I was doing the first testing I asked the person shooting the 308 what they thought about the brake versus the can. Subjectively they said it wasn't much different. I am dead sure that the effect could be measured as the brake being better for recoil but like sound levels, there are other factors that make the rifle "seem" to recoil less. There is certainly less flinch inducing from a suppressor versus a brake.
More discussion on this topic will do the shooting community a lot of good.
The NIOSH doc is focussed on continuous noise. Noise dose modelling and its associated damage/risk criteria are relevant to this type of noise but not impulse noise. With the latter, you need to keep exposure to-any- impulse events under 140dBSPL (peak).
There is a somewhat separate (and much smaller) volume of literature on impulse noise. It is much more difficult to measure and requires far more expensive gear.
Yes the focus is on continuous but there is a specific section on impulse noise in 3.2 ceiling limit:
"The generally accepted ceiling limit of 140 dB peak SPL for impulsive noise is based on a report by Kryter et al. [1966]. Ward [1986] indicated that "this number was little more than a guess when it was first proposed." To date, a proposal for a different limit has not been supported. Henderson et al. [1991] indicated that the critical level for chinchillas is between 119 and 125 dB; and if a 20-dB adjustment is used to account for the difference in susceptibility between chinchillas and humans, the critical level extrapolated for humans would be between 139 and 145 dB. Based on the 85-dBA REL and the 3-dB exchange rate, the allowable exposure time at 140 dBA is less than 0.1 sec; thus, 140dBA is a reasonable ceiling limit for impulsive noise."
In the absence of any other data, this looks to be the only source that actually provides a guide for impulse noises between the 125 and 140 dBA ranges. Shooters will regularly experience levels in this range suppressed or with single layer of hearing protection for non magnum centerfire rifles. Braked and magnum shooters will exceed these limits with a single layer of hearing protection.
If there is more info available or better guides, I would like to see them.
Look the suppressors do reduce recoil , just not as much as a brake does , the only real research I can think of was done in Finland quite a few years ago , look that info up , they used I think a pendrulum device to measure the force , ie suppended from a pivot point etc .
In all the impulse literature I've read, I can't say I've seen detailed focus on time/energy integration. The tone of that sounds rather speculative.
Those refs quoted are very familiar to me- I did a Masters thesis on noise induced hearing loss in 1991 and most of the literature wasn't fresh even then.
It may be speculative, but for the moment it is all I have seen. This is why I am trying to pin down some quantifiable numbers from real professionals like yourself who have the background necessary to understand the studies. I have approached this topic in forums around the world and not one individual will say XYZ is safe levels.
At least with that report, you can take a gunshot duration of around 20ms and say that some quantifiable number of shots in an 8hr day at a given dBA rating will be "safe". Without any other data to go on, what are those of us in shooting community to do? It may not be perfect but at least it is something. I would rather get a perfect set of data that a professional will stand behind but I have to think it either is too expensive to do the testing, or liability issues prevent anyone from attempting the study.
I have an accelerometer in my sound testing kit. I just haven't set it up yet. As soon as I catch up I will see if I can provide another set of data points with a different tool for comparison of brakes and suppressors. I know suppressors reduce the perceived recoil significantly. I am just not sure how much of the perception is due to the lowered sound. I am positive that a brake will redirect gas more efficiently in a shorter period of time.
My opinion is that the gas in a can will interact for a longer period of time and smooth the impulse that is felt. Sort of like slowing down from 100k can be done by hitting a wall in 1 second or stepping on the brakes for 10 seconds. The energy goes somewhere either way.
@ODL any plans for a thread on over barrel hunting can for bolt actions? Something light & short for a .260 perhaps
The guy who did the massive muzzle brake test on precision shooting measured the forces.
This link has a summary of results, scroll down for the suppressor. Not sure if he posts the actual graph for the suppressor anywhere though.
Muzzle Brakes: Recoil Results for 308 & 300 Magnum - PrecisionRifleBlog.com
Yes, it is soon. I am finishing off some QD jobs with one starting production and the other is close. I set the A2 aside for now.
Short is relative. The Ratchet Lock is about 190 from the shoulder and is about 138 dBA at the muzzle which would put it around 130 at the ear for a bolt gun. I am not keen on shortening it up too much and losing the sound. That is why I am very interested in this thread though and some opinions of professionals in the hearing industry.
100mm ish forward seems like a good size.
Keen to see the QD available