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Moderator Exit Hole Test

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OldSpook

OldSpook

Member
Apr 25, 2021
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Virginia, United States
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@JimNM ;) Here you go. Interesting result. I converted the dB readings to KW so that I would have a linear measurement to put in the graphs as that is much more intuitive for most folks. The KW number is actually meaningless. It is just done here so that we get a linear relationship to make the graphs more readable. The high spike on the left of the x axis is the bare rifle with no moderator. You will also see some data for a Tanto and one of my home brew moderators. I did not graph that.

hole-diameter-test-ss-data.jpg
hole-diameter-test-graph-data.jpg

It seems that hole diameter doesn't make a lot of difference in front of the rifle but sure makes a difference toward the sides? More samples at different locations would be more conclusive but this satisfies me. If someone wants to take the five moderators I made for the test and continue to run with it I'll ship them. Be advised they are threaded for a Diana Stormrider and likely will not fit anything else being M10 x 1.0 & recessed 5mm. Also they won't have any particular other use as they are pretty flimsy. They might last a few hundred shots.
 
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Not sure this will help. My two most quiet guns are A HW110 &HW44, in 22 Cal, with factory Mods both so quiet I have to shoot over a Chrono to make sure they are spitting out pellets. I use 3 meters to test and I place the meters at random positions. Front, side 6ft 4ft ect.ect; I don't have the readings with me.[sorry]
This is how Weihrauch does it [along with good tunes OfCourse] both 7" long x1 1/8 They have baffles/inserts [not sure to be honest] about 1/3
and another at 2/3 in The hole size in the insert is about 6.92mm and the exit hole is about 7.35mm It's also filled with a honeycomb material that is
blue in color. Both Fun guns and a Hoot to shoot. For what it's worth.
 
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bink2 said:
Not sure this will help. My two most quiet guns are A HW110 &HW44, in 22 Cal, with factory Mods both so quiet I have to shoot over a Chrono to make sure they are spitting out pellets. I use 3 meters to test and I place the meters at random positions. Front, side 6ft 4ft ect.ect; I don't have the readings with me.[sorry]
This is how Weihrauch does it [along with good tunes OfCourse] both 7" long x1 1/8 They have baffles/inserts [not sure to be honest] about 1/3
and another at 2/3 in The hole size in the insert is about 6.92mm and the exit hole is about 7.35mm It's also filled with a honeycomb material that is
blue in color. Both Fun guns and a Hoot to shoot. For what it's worth.
Click to expand...
63mm and 96mm, from the muzzle... Yep. That baffle set is 159mm long. My HW110 is now the quietest moderator I have ever tested that came stock with a rifle. Actually it is the quietest moderator I have ever tested period but it IS NOT the most efficient I have tested. I do like my 110. Sweet rifle.
 
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OldSpook said:
63mm and 96mm, from the muzzle... Yep. That baffle set is 159mm long. My HW110 is now the quietest moderator I have ever tested that came stock with a rifle. Actually it is the quietest moderator I have ever tested period but it IS NOT the most efficient I have tested. I do like my 110. Sweet rifle.
Click to expand...
Any idea what the innards are? honeycomb blue stuff and all? -interesting and very effective. I wish I could get the newest Weihrauch Mods.
UK has them but OfCourse can't ship here.
Hope you don't mind but I have to ask. Which brand do you believe is most efficient? and yes you can say your own[LOL]
 
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bink2 said:
Any idea what the innards are? honeycomb blue stuff and all? -interesting and very effective. I wish I could get the newest Weihrauch Mods.
UK has them but OfCourse can't ship here.
Hope you don't mind but I have to ask. Which brand do you believe is most efficient? and yes you can say your own[LOL]
Click to expand...

Home

huggettmoderators.com huggettmoderators.com
 
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d3vnull said:
Here is where you get the Weihrauch moderator in the U.S. Might want to contact them on thread size first since not stated.

https://penchetta.com/weihrauch-hw100-moderator-ldc-177-22/
Click to expand...
Thanks for the reply d3null
I checked it out, and that is the older version, the new versions are called the XL and XL-K they both look to be a bigger diameter
and shorter. I did order a Hugget Astille I hope it performs better than it looks I expect great things from it [LOL]
 
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Well I think the data shows there is probably a linear relationship between the diameter of the hole in the muzzle and the distance between the half power points in front of the moderator.

IOW The moderator functions a little like a cheerleaders megaphone in that it directs the noise forward. The smaller the hole, the tighter the angle. In order to get really effective moderation directly in front of the shooter you literally have to reduce the hole to a diameter smaller than the bore... That requires the use of wipe(s) and those reduce accuracy.
 
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steve-l said:
I have been making moderators for years and assuming the moderator is in perfect barrel alignment pellet/bullet clearance to moderator bore has very little effect on how quiet the moderator is. I now use .020" diametral clearance between pellet and moderator bore pretty much as my standard. Other things are much more important.
Click to expand...
First point: The numbers are the numbers. They strongly indicate that the size of the muzzle exit has a distinct impact upon the quietness of the moderator in certain directions from the muzzle. A further test, not shown here indicated that that impact increased as you moved further around the clock from the muzzle. That is to say at 3 o'clock the diameter of the hole in the muzzle had the MOST impact upon the noise level and at 12 o'clock the diameter of the hole in the muzzle had the least effect upon the noise level measured.

Second point: 0.02 inches? That's pretty tight. Assuming perfection is a fast way to failure in a production environment. So I am going to make the assumption that you are building custom moderators for specific rifles. You try to go into production with that kind of clearance and you'll have more moderators that clip than ones that don't.

HW110 moderator, which is very quiet takes a 7mm allen wrench to remove the muzzle cap. It is a .177 moderator. That is about 1.25mm windage on a 170mm run.
 
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OldSpook said:
First point: The numbers are the numbers. They strongly indicate that the size of the muzzle exit has a distinct impact upon the quietness of the moderator in certain directions from the muzzle. A further test, not shown here indicated that that impact increased as you moved further around the clock from the muzzle. That is to say at 3 o'clock the diameter of the hole in the muzzle had the MOST impact upon the noise level and at 12 o'clock the diameter of the hole in the muzzle had the least effect upon the noise level measured.

Second point: 0.02 inches? That's pretty tight. Assuming perfection is a fast way to failure in a production environment. So I am going to make the assumption that you are building custom moderators for specific rifles. You try to go into production with that kind of clearance and you'll have more moderators that clip than ones that don't.

HW110 moderator, which is very quiet takes a 7mm allen wrench to remove the muzzle cap. It is a .177 moderator. That is about 1.25mm windage on a 170mm run.
Click to expand...
In my world .020" is huge. Yes, you are correct, I make my moderators for specific rifles. I do also use a test rod the exact diameter of the exiting pellet (barrel size at choke) to make certain the moderator is centered to the barrel after installation.
 
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steve-l said:
In my world .020" is huge. Yes, you are correct, I make my moderators for specific rifles. I do also use a test rod the exact diameter of the exiting pellet (barrel size at choke) to make certain the moderator is centered to the barrel after installation.
Click to expand...
I admire someone who has that kind of technical skill and the equipment to implement it. I do not. I appreciate precision work as much as the next guy. And I thank you for the advice.
 
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