Moderator for HW98 ?

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Mg616

Mg616

Member
Jan 21, 2021
335
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grand rapids MI, United States
Your $.02 please...looking to quiet my 98 a tad for subdivision backyard duty, any experience with the Weihrauch moderator or others? noise reduction, point of impact change, affect on cocking cycle etc. ? Thanks

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Nice looking rifle! I've got one in .20. I put a moderator on mine for a while but took it off as I did not perceive there was all that much improvement. I think there probably was, as the moderator works a treat on my Condor, but the rifle is already reasonably quiet in .20. One of the things you will run into when moderating a break barrel is the fact that most silencers will not take the constant wear and tear they see on the end of that barrel. They do fine on fixed barrel rifles but are not generally designed for being an actual handle on the end of a lever.

Maybe some folks will chime in with a recommendation that can take the rough handling. I don't know of any but surely someone builds extra beefy silencers for break barrels?
 
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I have a Weihrauch clamp-on moderator on my HW30 and I like the sound better. The clamp-on fit was a little sloppy and I used plumbing thread tape to tighten it up. I don’t remember if there was a POI shift. I never pulled on the moderator to charge the spring piston. There is also a UNF adaptor for my HW97 with a Huggett Belita. I threw a drop-in kit and polished the internals of the HW97 and it’s much more enjoyable to shoot, the moderator is like icing on the cake. I’ve read on forums and seen videos saying that a moderator is useless on a springer, but my ears are happier with a moderator on my boingers. If they don’t bring down the dB much, they at least change the pitch or tone so that it’s less offensive to me.
 
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i use one on my b-barrels... example:
Click to expand...

Excellent study, Frank. Well done.

Let's talk about what you have measured.

moderated-break-barrel.1623441673.jpg


This chart is an analysis of the data you captured. Your methodology looked excellent. Working in the shop with low noise certainly improved your readings and I think you data capture can't be faulted. That gives us some good hard data.

First interesting point: Your data shows that the actual noise impulse at the muzzle was not only reduced substantially but it was made more consistent. The SD of the noise impulses was reduced by 4.4 dB. That's a lot. Consistency of the noise impulse was made 358% more consistent.

Second point: Your average reduction was 10.6 dB. That's huge. Lets interpret that. 

Decibels is a measure of power. If you increase a signal (noise impulse) by 3 dB you have doubled the actual power of the impulse. That means the range at which it will be detected is increased by 140%. If it could be heard at 100 yards before it would now be heard at 140 yards. If you reduce the signal by 6 dB you have cut the power by a factor of 4 and the range by a factor of 2. If your shot could be detected at 200 yards it is now detectable at only less than 100 yards. You have shown a power reduction of 10.6 dB. We can work that out from the following table:

-3dB = .707 .

-6dB= .707*.707 = .499...

-9dB= .707*.499 = .354

The SD on your data is 1.7 dB so we can just the assertion that your data shows the range at which the shot can just be detected by the human ear has been reduced by a factor of (1/.354)=282 percent. That's quit a bit more than I expected. That goes to show you just how your ears can fool you and how important it is to actually do real measurements and run the math.

So for the OP, he has shown you that the moderator he used in the test will the reduce range at which someone can hear your rifle by 282 percent. If your rifle could be heard before at 150 yards, after the moderator that person would only be able to detect the shot (at the most) at 150*.354 = 53 yards.

Quite an improvement.

From yuur data we can also make an estimate of the range at which the noise of the shot will be reduced to the level of the noise floor. The noise floor is also called the "ambient noise level". In the video it looks to be about 38 dB. That is pretty quiet. The distance from the muzzle looks to be about five inches so I'll work with that, an exact measurement from the muzzle would make the following calculation more precise, but we have good enough data for our purpose. 

With a noise floor of 38 dB and an average shot level of 88 dB we need to loose 50 dB by "moving" away from the rifle. 50dB divided by 6 = 8 (remember we have to double the range for each 6 dB change). Now we double the range 8 times. We get 10, 20, 40, 80, 160, 320, 640, 1280 (inches). 1280 inches is 106 feet. Now we still have 2 decibels left and that is almost another 40 percent in range (3 dB) so lets call it 50 yards (150 feet). At 150 feet the sound of that rifle will disappear into the background noise (of his shop) out doors the noise floor will probably be higher most of the time, especially in an urban or suburban area.

We can work backwards from that estimate to estimate how far away the unmoderated Parrus can be heard above the noise floor. We multiply 150 * 282% (from above) and get about 423 feet. Clearly these are only educated guesses but they will be close enough for anyone's purposes.

So there you go. Now all you have to do is decide if you want to chance accidentally grabbing that moderator when you are cocking the rifle, clearly there is an advantage to having the moderator on the rifle. Maybe someone who makes moderators will read this and figure out how to make a really tough moderator for careless folks like me.
 
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My HW98 .20 is the "old" model and my .177 and .25 are the "new" model HW98s.

None of them (all three) are loud enough for a "silencer" and as far as a weight to balance the barrel or "moderate" vibration I've not had any problems at all with new or old HW98s.

The .177 HW98 is a "new one" with serial number number 2321860; it has the unscrewing "muzzle" device that either balances or abates the rifle or muzzle "blast".

This rifle has my Hawke 4-12X 40mm (Airmax 13130) and shoots inside Sports Match Rings with a studded rear ring mount.

Eventually if I want to be serious about this .177 HW98 I will HAVE to install Diana Zero Recoil Mounts and proceed THAT WAY and NO OTHER WAY no matter what anyone says about mounting a scope fixed instead of on recoilless rails presented by Diana since generations ago.

Fixed mounts on an HW98 are not going to last even though the rifle is "heavy" to shoot and hold and "supposed" to "soak" up recoil.

Look into your GLASS and whether it is expensive enough to last or GET a ZERO recoil mount system to SAVE the scope of your choice.

But a moderator for the HW98 in noise or balance doesn't make sense to me.

All my HW 98s without suppressor moderators are already ALL READY quiet as a mouse outside.

Just my observations with the HW98s I have and why they are substantially perfect in every way clear out to taking hunting in the field without further ado that garage mechanics do to RUIN a perfect rifle!
 
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