Moderator test chart

Leica Fortis 6 - Bright and powerful.
The test conditions:

Prior to the test all mods had been cleaned in an industial ultrasonic bath and then thoroughly dryed.
All shots were taken from two identical Mauser 98 rifles with 20" barrels. The amunition used was Hornady Match 168grs. BTHP.
The first shot was taken through a cold moderator, follow by 4 consecutive shots. The mods were then blown out and cooled down. This procedure was then repeated and the mods cooled down and blown out again. The last shot was a third first-round-shot through a cold mod. The resulting values were then averaged.
The measurements were taken 1m beside the muzzle and 1.5m above the ground in soundproofed surroundings.
The equipment used was a class 1 Bruel & Kjaer 2250.
 
Interesting. I like the attenuation per gram statistic, I have not seen that before. Moderator choice is a series of massive compromises, but weight versus noise reduction is probably the one most of people obsess about.

Does anyone know how to get this into excel?
 
muddy42 said:
Interesting. I like the attenuation per gram statistic, I have not seen that before. Moderator choice is a series of massive compromises, but weight versus noise reduction is probably the one most of people obsess about.

Does anyone know how to get this into excel?
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Agreed - really shows the ”capability” of the F&D mods :thumb:
 
wytonpjs said:
Agreed - really shows the ”capability” of the F&D mods :thumb:
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Absolutely! Even though I have to say that the absolute attenuation of my F&D 196 is at the bottom end of what is sensible for a .308. But at least I know what I am NOT carrying around with me 🤣.
 
Rider said:
Absolutely! Even though I have to say that the absolute attenuation of my F&D 196 is at the bottom end of what is sensible for a .308. But at least I know what I am NOT carrying around with me 🤣.
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I don't find it too loud on my .308 whilst stalking but I'm quite deaf (so the wife tells me :coat: ) and I wear hearing protection on ranges. Really tempted to go for a .243 FW149:norty:
 
Rider said:
The test conditions:

Prior to the test all mods had been cleaned in an industial ultrasonic bath and then thoroughly dryed.
All shots were taken from two identical Mauser 98 rifles with 20" barrels. The amunition used was Hornady Match 168grs. BTHP.
The first shot was taken through a cold moderator, follow by 4 consecutive shots. The mods were then blown out and cooled down. This procedure was then repeated and the mods cooled down and blown out again. The last shot was a third first-round-shot through a cold mod. The resulting values were then averaged.
The measurements were taken 1m beside the muzzle and 1.5m above the ground in soundproofed surroundings.
The equipment used was a class 1 Bruel & Kjaer 2250.
Click to expand...
Ahh, those crazy Germans. Quoting numbers to four decimal places :confused:. Lending spurious authenticity.

Fundamentally just one calibre (.308), one rifle, one barrel length, presumably one loading. Fine up to a point, and obviously impractical to test the whole lot again with a few variations. But they might have done that for a few of their top trumps.

TBH the weight thing is IMO a red herring, providing the rifle balances nicely. Want to save a few 100 grams, well have a pee and a poo beforehand, or eat fewer pies ;)

Interesting nevertheless. The net length, weight and diameter particularly. The Ase Utra SL5i catches my eye as I know it to be highly durable and maintenance free, which matters to me. Confirming my intention to get one. If they had also published a scale of price, and price per gram, even price per shot, using manufacturers' figures I suppose, that might have looked interesting. The dB figures were broadly interesting, clearly there are a few mods. out there that are pretty much useless, whereas most seem to be good enough at protecting the user's hearing. Not sure the attempt at guesstimating downrange noise was much use, given that the quarry will have been hit by the bullet before the noise catches up, and even then the supersonic crack will outweigh any diffuse, not easily located, boom or hiss from the can.
 
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Sharpie said:
Ahh, those crazy Germans. Quoting numbers to four decimal places :confused:. Lending spurious authenticity.

Fundamentally just one calibre (.308), one rifle, one barrel length, presumably one loading. Fine up to a point, and obviously impractical to test the whole lot again with a few variations. But they might have done that for a few of their top trumps.

TBH the weight thing is IMO a red herring, providing the rifle balances nicely. Want to save a few 100 grams, well have a pee and a poo beforehand, or eat fewer pies ;)

Interesting nevertheless. The net length, weight and diameter particularly. The Ase Utra SL5i catches my eye as I know it to be highly durable and maintenance free, which matters to me. Confirming my intention to get one. If they had also published a scale of price, and price per gram, even price per shot, using manufacturers' figures I suppose, that might have looked interesting. The dB figures were broadly interesting, clearly there are a few mods. out there that are pretty much useless, whereas most seem to be good enough at protecting the user's hearing. Not sure the attempt at guesstimating downrange noise was much use, given that the quarry will have been hit by the bullet before the noise catches up, and even then the supersonic crack will outweigh any diffuse, not easily located, boom or hiss from the can.
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You can make your own statistics if you PM me your e-mail address. I‘ll forward you the raw data then.

Downrange noise? Who the f*** cares? My quarry doesn‘t return the fire.
And as for weight, I am about as fit as possible, but still try to minimize equipment weight where ever possible. If I can reduce a weight which is attached to my muzzle by only 50 grams this what I will do.
 
Dr. Strangelove said:
Out of interest, is there before and after data for actual measured peak noise level? I had a look through the article and couldn’t see it, only dB reduction amount.
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I presume that that was the reduction from the unmoderated rifle, as you say, unspecified.

I suppose that putting the sound meter 1 m beside the muzzle and 1.5m above the ground was a constant, and maybe some sort of standard. But really who shoots with their ears 1 m beside the muzzle ? It's hardly a real world test. Dunno what I would have done better, but I certainly would have placed the meter somewhere more representative. As it happens Brüel & Kjær do make things designed for just this: Head and Torso Simulator – HATS | Brüel & Kjær
Rider said:
You can make your own statistics if you PM me your e-mail address. I‘ll forward you the raw data then.

Downrange noise? Who the f*** cares? My quarry doesn‘t return the fire.
And as for weight, I am about as fit as possible, but still try to minimize equipment weight where ever possible. If I can reduce a weight which is attached to my muzzle by only 50 grams this what I will do.
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Thanks, but I'm not really interested in seeing the raw data nor massaging it uselessly. The magazine put it out there, they way they chose. Some of which I found useful. I could mess about with it, but to what purpose really ? I'm certainly not going to research the missing data that would have been so easy for the magazine to include. Unless that is included in your raw data ?

As for weight, well I too try to minimise my burden within reason. And have done some serious backpacking where it truly did matter. But for stalking, well just choosing a lighter weight knife with a polymer sheath rather than heavy leather, leaving the spare behind, discarding that folding gambrel and hoist, and all the other superfluous stuff that you never actually use, wearing lighter boots (this really helps), taking enough rounds to realistically use, not two or three magazines full, etc. etc. and you can shave off kilos. and have a better experience. Do you actually ever shoot prone off that bipod or just off sticks ? If not, why leave it attached ? What weight are those binos hanging around your neck ? TBH I'd feel naked without my heavy rangefinder binos, but when not stalking its just my excellent tiny wide angle lightweight 6x32s, which would be even better suited to woodland and save maybe 500 grams when stalking at "point and shoot" ranges. As for simply the weight of your 'scope, well if you must have that megazoom 56mm objective 30mm tubed thing with umpteen dials, fine. But perhaps something slimmer and much lighter might serve you better.

As I get even older I am becoming more minimalist and less inclined to buy more stuff. Which doesn't sell magazines and advertising, sorry about that.
 
Without going in to an in-depth analyses, it looks as if 4 out of 5 moderators reduce the noise of the shot by around 28-31 Db. A few outperform that, and a few fall behind. My question is, can the human ear distinguish between a shot that is 82Db and one that is 86Db?
I do understand that hearing damage is a result of repeated exposure to noise - so if I was a target shooter, I would look for the highest possible noise reduction, even if that is expensive.
But as a deer stalker, typically taking 1-2 shots per week....does it really matter? Built quality, weight and price becomes a more important consideration.
 
Erik Hamburger said:
so if I was a target shooter, I would look for the highest possible noise reduction, even if that is expensive.
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Actually I don't think so. Every target shooter I know uses hearing protection as well, which can add a further 20dB or so at the ears. Those who also use moderators are I think doing so for potential benefits in accuracy (muzzle flip etc) and softer recoil. TBH a moderator as such is unlikely to benefit fundamental accuracy, after all the bullet is in free flight by the time it has left the muzzle and is into the moderator. But reduction in blast effects on the free-flying bullet might help, with a well designed precisely aligned mod. A poorly designed or aligned one could make things worse.

For a target shooter I suggest that durability, and low maintenance, is a fundamental requirement, not addressed in this study. Neither is accuracy, which surely should have been straightforward to measure whilst doing the tests. Weight much less of a consideration.
 
Please don't ask me for the source, as I really don't know. But I have heard (no pun intended) that in order to permanentely protect your hearing impluse noise should be kept below 137 dB.

So when we are assessing moderators for stalking we have to take more factors into account than just the pure performamce of the mods, most importantly the calibre and the barrel length. Only the combination of these will determine if a mod is fit for purpose in a specific case. An 18" .30-06 will need a significantly more powerfull mod than a 22" .308.
There isn't THE best moderator. It all depends on the circumstances and requirements.
 
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