Taming the bark of an Avenger

[rangerfredbob]

Long time no post, life gets in the way of things... I still have all my stuff plus some, just been building a shop for myself and catching up on maintenance of my other junk I've been putting off

Anywho, when the Avenger first came out I ordered one in .177 and immediately degassed it and set everything to minimum for shot count since that setting is more than sufficient for my pesting needs... haven't put it to the chrony or done a shot count but the regulator is at 1000psi and it gets lots of shots...

That said I'm spoiled by my Marauders, the Avenger isn't loud but it isn't quiet either... I did some looking and it looks like there's some 3D printed options that don't look too bad (don't want to break the bank or be super long so the DonnyFL and added moderator is out...), namely from Buck Rail and GeoffK but having a hard time choosing between the two... I have plenty of space so I'm not worried about it being loud for me, mainly because it spooks my targets where my .22 marauder with bstaley mod and some foam in the tube doesn't... and like the addage, .177 does work good on feathers...

So, thoughts?

Hoping to get my shop done this summer so I can start tinkering again...

[rdtricks]

Watched a Youtube video by "Airgun Detective" ( ) of this man's goods today - https://buck-rail.com/product/air-venturi-avenger-suppressor/.  I like what the video showed and the prices surely can't be beaten.  I have actually reached out to ask if moderators for my Nova Liberties can be manufactured.  Take a look and tell us what you think.

[RunsOnAir]

Many hunters have mentioned that the loudest sound in the target area often doesn't come from the airgun report but the impact itself.
I have Geoffk's internal baffle system on my 22 cal Avenger and am very happy with it. I have never felt the need to add another sound moderating device on that air rifle, but I'm shooting it from a bench/table at distances beyond 30 yards. My observation when sparrows made the mistake to land in my field of view corroborates the hunters' statements: The remaining sparrows take flight after I shot one of them, but sometimes they decide to land closer to me. That's all I need to know that I'm fine sound wise.

[runner57us]

I have a .22 Avenger and have compared the Buck Rail 3D printed moderator and another from eBay made by benelliboym1.  They are both shown in the picture attached.  benelliboym1 on top and Buck Rail on the bottom.

Using only my ear they both make a large difference in quieting down the Avenger compared to without any moderator.  It goes from a gun I would not shoot outside with the neighbors without fear of being detected to one in which I might be able to shoot and not have anyone take much notice depending upon how far away they were and what other noises were going on at the time.  The Avenger without any moderation to my ear would immediately be heard and generate concern that someone was discharging a firearm in the area.  I know this description is subject to interpretation and I wish I had a dB meter as I would rather provide quantitative results.  But I don't.

Both the 3D moderators are roughly the same length.  The Buck Rail does not go into the barrel shroud as far.  Measuring on my rifle the barrel is 3.25 inches inside the end of the shroud.  The portion of the Buck Rail that goes inside the shroud is 2.75 inches.  So it does not actually contact the barrel.  I am not sure if that is by design but I would think so as it does not have any venting along its length.  The portion of the Buck Rail that projects outside the end of the shroud is 4 inches.  It has a small honeycomb-type pattern.

The benelliboym1 moderator portion inside the shroud is 4 inches and the outside portion is 2.5 inches.  So it appears that the inside portion actually contacts and supports the end of the barrel.  It has four slits to allow air to be released inside the shroud equally spaced around the circumference.  The outside portion has a carbon fiber checkboard-type pattern.

Concerning performance both of the 3D moderators once installed did not seem to change the POI or grouping sizes from no moderator for me.  Although both work well and I would be equally happy with either one versus no moderator if I am forced to award the first place then I would give a slight edge to the benelliboym1 moderator.  To my ear, it is slightly quieter and the sound produced seems a bit more muted.  I must stress it is a very slight difference and so close that someone else might come out with the opposite opinion with their ears.

I hope the information is helpful for you to make a decision.  I believe you would be suitably happy with either one compared to none.  I have no association with either moderator manufacturer and I purchased both with my own funds.

[JimD]

I bought a buck rail suppressor for my Prod and tested it with my inexpensive Amazon sound meter at 15 feet.  I don't test next to me because I don't care how loud it is next to me.  15 feet is handy and is still closer to me than my neighbors would be so I think it's more what I want to know.  My measurements before and after tests were both about 85db.  They varied only a few db from shot to shot.  It seems like in the test on the video he had a test around 85 without but then two tests over 90 db.  Curious why there was that much variation. 

My conclusion is that the buck rail moderator changed the tone of the report but not the loudness.  It sounds different and perhaps less objectionable.  But I don't think it is less loud.

I've also tested my 25 caliber Avenger.  The regulator is a lot higher, it is set at about 2100 and it's making about 45 fpe.  The report is over 110 db.  MUCH louder than the little Prod.  I'm sure yours is quieter turned down a lot but it would be interesting to see a measurement.  I think the meter I'm using was only about $20. 

I don't trust anybody's impression of the improvement from a surpressor (including my own).  Comments without measurments are not very useful in my opinion.

I have a DonnyFL adapter on my Avenger but no moderator at the moment.  I made one and used it for awhile but the diameter was too large for the cover over the fill port to come off.  So I had to take it off to fill the gun,  I think the threads got worn by this and it now clips.  I will use a slim moderator if I put one back on the Avenger.  For now it is a range gun, I use the Prod or my P35 around the house. 

[jjohnsonlta]

I bought the one from Benelliboym1 for my Origin. It definitely made a difference. I just ordered one for a Beeman 1358 because I liked that it's not as long externally as some.
 

[drift shooter]

Has anyone tried the strip stack pac from Hajimoto Productions ? Watched the install video , seems a little more involved but would be no issues of it being a "suppressor".

[rangerfredbob]

Well, I decided to give Buck Rail a shot... price is right and sounds like a stand up company... plus while there might as well throw a couple LDC's for Crosman 13XX/22XX and some scope mounts for the same...

[runner57us]

I don't trust anybody's impression of the improvement from a surpressor (including my own).  Comments without measurments are not very useful in my opinion.

Fair enough and no argument from me.  $20 Amazon meter ordered and I will take measurements when it arrives next week and post the results.



I ordered this one because I have some electronics test equipment for a couple years from this company and they have been very reliable and accurate when compared to Fluke equipment.  I am assuming the same for the sound meter they produce.

[Ribbonstone]

Have used a meter much like that one ($30-38 at the time) and my shooting buddy at the time bought a different unit (about $70 at the time).

Of course they didn’t agree by numbers…was like trying to decide what air gauge to believe (the tank’s or the rifle’s)….but did agree that “A” as louder than “B”, just didn’t agree about the dB reading.  We have a tendency to believe the more expensive unit (and many times it’s like believing the better dressed witness).
 
Knowing which was measurably quieter than the other was all I wanted to know, wasn’t claiming lab values...basically was an objective value rather than a subjective one.

Can get all wrapped up in lower dB numbers that you can’t notice by subjective human ears. 

--------

As much as we don’t want to add length, adding an extension to a shroud does make it measurably quieter...basically more baffles AND more expansion volume.  Call them want you will, but are basically LDC’s.

We like short OAL….but don’t like shorter barrels...so the maker limits the amount of shroud ahead of the muzzle.  That muzzle to end cap length seems to be where most of the “quiet” happens.

[RunsOnAir]

I am no doctor or fine connoisseur of the human body, but our ears are not perceiving sounds in a perfect way. We are more sensitive to some frequencies than others. It's even more true for animals.
also, at identical decibel level, some sounds pierce ambient background (city sound?) more than others.
The frequency/pitch of a sound will also carry differently over distances.

I believe the goal of sound moderation is as to not spook neighbors or prey.
In that aspect, at least regarding neighbors, I believe some air guns are going to sound stealthier than others due to pitch/frequency of the sound made rather than pure loudness, and how well they blend with the existing background.
For animals, I have no clue what their ears perceive so I won't speculate.

So my point I believe is that instrument measures are not necessarily everything we should keep into consideration. It's not about averaging the sound level from voices and instruments in a concert venue or a church hall.

Just my $0.02 of unscientific take on how to approach the possible answers to 'taming the bark of an avenger'

[AKM]

Very well said RunsOnAir,

Also the terrain of the land and foliage can make a big difference in how sound travels.
So many variables.

[JimD]

There is a sticky about moderator tests.  The latest tests were a different rifle but a previous series of tests was an avenger.  There is a link to the older tests in the newer test thread.  Some of the tested moderators were pretty inexpensive. 

[subscriber]

There is a sticky about moderator tests.  The latest tests were a different rifle but a previous series of tests was an avenger.  There is a link to the older tests in the newer test thread.  Some of the tested moderators were pretty inexpensive.

Here:  https://www.gatewaytoairguns.org/GTA/index.php?topic=182738.0

And here:  https://www.gatewaytoairguns.org/GTA/index.php?topic=180075.0

[Tomygun1]

rangerfredbob,
Your Avenger will shoot as silently as you make it with mods.     My 25cal at full volume is now among my quietest PCP rifles of any cal.

[runner57us]

I have a .22 Avenger and have compared the Buck Rail 3D printed moderator and another from eBay made by benelliboym1.  They are both shown in the picture attached.  benelliboym1 on top and Buck Rail on the bottom.

Test completed.  Sound meter placed 15ft in front of the rifle with the sensor pointed directly back at the rifle.  Fast sample and Hold.  Shooting immediately over the top of the meter.  Three shots each and then averaged.  Regulator at 1300 psi with Avenger .22 firing Crossman Premier Hollow Point.

Buck Rail 3D       - 86.0, 84.3, 85.3 Average 85.3 dB
benelliboym1 3D - 83.2, 84.0, 83.6 Average 83.6 dB
No Moderator      - 90.8, 92.2, 90.3 Average 91.1 dB

[subscriber]

Thanks John,

A 3 dB reduction is about where people can just tell a difference.  But would tend to declare it, "not significant".   Perhaps satisfied customers notice the difference in tone, or "ramp rate", rather than peak sound level reduction as measured with a meter?

How far away was your target or trap?  I ask because of the possibility that the projectile impact noise becomes the loudest noise and was still significant.  Is there a hard wall directly behind the trap that could reflect sound towards you? 

Listening to test videos of Buck Rail suppressors,  where the trap is far away, or the shot is into a lawn (or loose dirt), suggests a greater than 3 dB reduction (in some installations).  See video in 5th paragraph.

Now, many people scoff at video sound reduction comparisons.  Yes, auto levelling messes with the sound captured and reproduced.  However, auto sound levelling does not flatter moderator performance; it makes it seem less effective:  This is because auto levelling reduces loud sounds and boosts quieter ones.  So, they would make a suppressor seem less effective than they are. 

Here is an example of a Buck-Rail silencer.  Unfortunately, without instrumented measurements.  Jump to 50 seconds into the video for a with/without comparison - fired in a direction to avoid projectile impact noise: 
https://buck-rail.com/wp-content/uploads/2021/03/Diana-Chaser-Silencer.mp4?_=1

It case it is not obvious, none of this is heckling your results.  I am trying to understand how some people are very happy with a given product, while others declare "not much difference".  Perhaps it is a matter of expectation, and that some use measurements and want to see much lower dB, or else declare a "fail". 

In my opinion anything on the 85 to 80 db range is already "quiet", depending on how far away it was measured from the source.    I care most about the sound level and quality, at the distance the most opinionated ears are located.

The fact is that reducing a stock report from 100 to 90 is a lot easier than reducing a report from 90 to 80 db.  If we look at the 20 silencer test thread, there are a lot of expensive products that dropped a 30 FPE .22 to below 85 dB.   None reached below 79 dB with the setup as described in that thread:  https://www.gatewaytoairguns.org/GTA/index.php?topic=182738.msg156082548#msg156082548  Results quoted below:

Here are the results by category, beginning with dB (decibel) output averages of 3-shot readings:

Sorted by dB Low to High:

79.0 Huma 40mm Std
79.1 A.U.O.
79.4 Huma 30mm (modified)
79.5 Rocker2
79.6 MM-1
79.6 Neil Clague
79.9 FX Factory (modified)
80.0 Wolf 30mm
80.2 DonnyFL Sumo
80.9 Rocker1
81.3 0dB 110C
81.3 STO Falx
81.4 Wolf 35mm
81.5 Geo Hunter
82.9 Geo Short
83.3 TKO Slim
83.4 MM-2
83.7 DonnyFL Tanto
86.8 Amazon Pill Box (modified)
91.9 HT-68 Fluid Damped
105.2 bare barrel (meter overloaded)

Interestingly some of the louder silencers from the earlier test (shot from the shrouded Avenger), performed better in this new test through a straight barreled gun. For example the Neil Clague rose from 11th place to 6th when capturing the full air blast from the straight barrel.

The Huma 40mm Std did well in both tests, it was no.2 when shot through the shrouded Avenger and no.1 through the bare barrel AR6K.

The worst performing Wolf 30mm when shot through the shrouded Avenger, rose from 14th up to 5th when shot through today's bare barrel gun.  There were more position changes if you compare the tests:

https://www.gatewaytoairguns.org/GTA/index.php?topic=180075.0



Sorted by PRICE ($):

27   Geo Short     
29   Geo Hunter     
49   Wolf 30mm     
59   Wolf 35mm     
59   A.U.O.
65   Rocker1     
70   Rocker2   
80   FX factory (modified)
92   TKO Slim     
99   DonnyFL Tanto   
120 0B 110C   
125 Huma 30mm (modified)
129 STO Falx     
135 Neil Clague     
150 DonnyFL Sumo   
160 Huma 40mm Std
n/a Amazon Pill Box
n/a HT-68
n/a MM-1
n/a MM-2


Sorted by VOLUME in cu. in.:
(calculated from external dimensions only)

5.11   Rocker1
5.25   TKO Slim
5.49   Rocker2
5.68   0dB 110C
5.99   A.U.O.
5.99   MM-1
6.02   DonnyFL Tanto   
6.06   Geo Short     
7.33   MM-2
7.68   Geo Hunter     
8.32   Wolf 30mm     
8.72   FX Factory
8.96   Huma 30mm
11.25   Wolf 35mm     
12.10   DonnyFL Sumo   
12.44   Amazon Pill Box
12.70   STO Falx     
12.88   Neil Clague     
14.14   Huma 40mm Std   
15.70   HT-68 Fluid Damped

The sound deadening effect is dramatic going from bare barrel to almost any silencer. And it should be remembered that on the decibel scale, a doubling of intensity corresponds to an increase of 3 dB. This does not correspond to a perceived doubling of loudness, however. We perceive loudness to be doubled when the intensity increases by a factor of 10, which corresponds to a 10 dB increase.

Therefore, going from the bare barrel’s 105.2 dB reading (which could be even louder since it maxed out the meter) down to even the loudest silencer (91.9 dB from the HT-68) was more than 50% less in perceived loudness to the ear. It was a 13.3 dB reduction, or more than half the perceived loudness of the bare barrel.

Again it should be noted that in today’s test, by placing the dB meter almost directly in the line of fire of an un-shrouded bare barrel gun, the forward sound throw was more accurately measured and the loudness differences between the various silencers clearly magnified.

For example the spread between all silencers was only 12.9 dB (the HT-68’s 91.9 dB minus the Huma 40’s 79.0 dB) and the bare barrel output overwhelmed the meter into overload, measuring a maximum of 105.2 dB before the screen locked and started flashing.

Keeping in mind that a 10 dB increase creates a perceived doubling of sound to the human ear, this 12.9 dB spread means the output from the loudest silencer was more than twice as loud as the quietest. So the spread was easier to see when the meter was 50 feet downrange and almost in line with the muzzle.

It also appeared that silencers with more open internal structures that provide room for the incoming air to expand quickly, were more effective on shrouded or baffled guns, but units with more complex internals that directly engage the airflow and force it into convoluted patterns thereby delaying their exit time, seem better able to handle the full air blast from a straight barrel, while still working quite effectively on shrouded guns.

[soupyyy]

Here is a sound test of my no mod Liberty .22 in an urban area.  With my cheap sound meter anything under 84 dB reading is backyard friendly to me and at 80-82 dB I can take a shot or two at 2 AM without much concern.  My moderator is 3D printer very similar to the two mentioned above.  Use heavy pellet to reduce noise if you need to.

[subscriber]

Peter,

I found your test thread and videos on this very useful.  You should post a link.

I like your rearward shroud vent "troughs" on your integral printed "stack".  You could have more passages along the circumference that terminate at the first/second and third/fourth  baffle (etc), to prevent air taking a shortcut from the first to the fourth baffle along the grooves.  However, results are what count, so kudos.

EDIT:  You could even have separate sets of passages feeding the reflex space, from each of the four air stripper baffles, so there is no "shortcut" between them; except for the common rear shroud volume.  Then, by the time flow or pressure waves from the fist baffle interacts with the fourth, bouncing off the rear of the shroud space, the pellet is long gone.

[Hawkeye51]

Peter
Your moderator looks great! My question is do you vent the shroud back at the breech end? I've seen some top dollar setups with multiple tiny holes in the shroud & sometimes in the proximal portion of the moderator. I personally put about 4 tiny holes staggered from an inch to 1 1/2 inches around the moderator at the breech end and wrap felt around the barrel under the holes. I drill holes in the shrould support so the air can get there, and use the full length. I have no idea if this helps, but it mentally makes me feel good about things, so I do it.