Q:

Making the .25 Edgun quiet, easily and inexpensively…

The key to the Edgun .25 making less noise is reducing the air pressure at the muzzle. There are a few ways to do this without engaging in exotic baffle designs, or spending money on an aftermarket shroud or moderator.

Here’s how it’s done:

The first step is to remove both the baffle cover, which is unscrewed counter clockwise, by hand, then removing the bottom shroud by removing the barrel bushing/vent nut. Then you can easily enlarge the existing vent holes at the rear of the Edgun shroud with a variable speed hand drill. I made my lower shroud vent holes 2.0mm in diameter:

You can go larger if you wish. If you go too large and begin to hear air “whoosh” out of the vent holes when firing, just wrap some felt around the inside of the shroud, behind the vent holes, to slow the air down. You can touch them up with the tip of a permanent ink black felt tip Sharpie. This is how they look when done, but before the Sharpie touchup:

The next step is to increase the air flow from the front of the Edgun to the rear of the shroud. Now on the R3 this is a bit more complicated because the shroud comes in two parts, so I will concentrate on the R3. Unscrew the top shroud, baffle cover, taking care to remove it easily because the O-ring can be damaged on the threads. Be sure to put silicone grease that O-ring before putting it back on. Note the bottom shroud, and barrel, are held in place by a 19mm nut with vent holes in it. It unscrews easily, counter-clockwise, with a common metric wrench:

After it is taken off, you then enlarge the holes in the nut with a variable speed drill. I went 2.5mm, you may choose to go smaller, but not much larger, as the hole diameter affects the strength of the nut.

After this is done, you simply replace the bottom shroud, then the barrel bushing, being certain that the bottom of the shroud is properly placed OVER the rim of the permanent cone shaped breech attachment. If you ignore this step, you will bend the bottom of the shroud when you tighten the nut…note the bottom of the shroud sitting flush against the cone shaped breech attachment in this picture. The hidden rim inside the shroud is about 1/8″ or so tall, but it must have the shroud placed evenly over it before tightening the nut. When you lift up and remove the bottom shroud, you will easily spot it, as the cone shaped breech attachment remains in place:

Finally, there has been much discussion regarding how much torque must be used to tighten the nut that holds the barrel and bottom shroud in place. This is not a difficult process. First you obtain a Russian Torque Wrench…see below picture:

Placing the 19mm wrench in this handy grasping tool, you tighten the nut to where it is snug against the shroud, then you go roughly 1/2 turn further. That’s all it takes. Remember, this is thin and fairly soft aluminum and will strip threads or bend rather easily. AND…if you have placed the bottom of the barrel shroud over the lip of the cone shaped breech attachment, you will not have bent, or dented, the bottom of the shroud.

Replacing the top shroud (baffle cover) is easily done, just be careful sliding the cover over the O-ring using a light downward pressure and clockwise screwing motion until it gets past the threads on the cover. Snug it up hand tight, no more.

That’s it! You can expect at least a 50% reduction in muzzle blast, which on the Long Edgun makes the hammer slap the loudest noise emitted when shooting the gun. It costs nothing, takes about 1/2 hour, a couple of metric bits, and a variable speed hand drill. Take your time. The existing holes will guide the bit if you proceed slowly, especially when starting the new hole.

Now, for that hammer slap…I’m still working on that one.

Regards,

Kindly ‘Ol Uncle H 😯 😯 t

EdGun

All Replies

Viewing 15 replies - 31 through 45 (of 323 total)

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Nah Syn,

It’s a sealed unit.

Gabe

quote rkr:

Non electric gaystates have a Harper valve system that eliminates the bounce, something like that could possibly be made for Edguns.
2) What’s Syria?

Syria is a third world country somewhere on the Arabic Peninsula. Nothing to worry about too much. Those non-electric gay states might be a reason for worry though. They may need some electricity and try to get it by any means … 😯

I was thinking “wind noise” from the muzzle blast. 😉

The scotch brite stuffing makes total sense with the difference in the noise! I assume you didn’t stuff the one piece?

Excuse my grammatical errors. I’m typing on my iPhone with my sausage fingers 😆

Gabe

Hoot,

Your right. I stuff the shroud with scotch brite. That may account for the difference.

Syn,

I use my iPhone mic to record the shots. I placed the phone about 6 inches ahead of the muzzle and 3 inches below. There room was silent. I made sure of that.

All I know is that I trust my hearing. If I didn’t, I’d be fucked..

Both shroud are relatively quiet for a 45 lb ft gun.

Gabe

Hard to tell, I don’t know how these were recorded exactly. We could be hearing some wind noise, the pellet impacting the towel in front of the back stop, room echo. I’ll make a few recordings with different mics and mic locations when I do mine.

My 177 EdGun gets over 150 shots per fill, hard to believe there is any wasted air from the hammer bouncing. 😯 I’m sure the hammer strike action in mine is a lot less harsh with the lower caliber.

quote Hoot:

I’m confused…

My ears told me the OEM shroud was loud. A modified OEM Edgun shroud was half as loud, or less. Neil’s single and double piece shrouds were both quieter, with the one piece shroud being a tad quieter than a fully modified OEM Edgun shroud. I believe Gabe’s OEM shroud had felt added to the lower shroud vent holes, which mine didn’t.

Neil’s two piece CF shroud was hands down quietest, and looked really nice on my .25 Long. Combine a decent baffled shroud with an oversized can on the end, and that’s serious quiet!

I have absolutely no idea WTF those charts indicate in the above posts. The one fact I did pick up on was rkr’s remark “Those clips seem to have at least one hammer bounce opening the firing valve, possibly even two. Killing that would reduce the noise level quite a lot. This brings up TWO important questions:

1) IS there a double hammer strike in the Edguns?
2) Can it be stopped, or tuned out?
2) Are rkr and synopsys “talking in technical tongues” that no one understands, and is not meaningfully interpreted to help us out? :whoop:
2) Is a HDD possible for an Edgun?
2) Should we stay away from Syria, and leave them to slaughter each other in peace…as is their Allah-given right?

1) There seems to be at least two valve openings in those recordings. You’d have to use less sensitive microphone to separate out each of them and to accurately count how many there are. Most PCPs have 2-4 valve openings due to the hammer bouncing against the firing valve.
2) Yes, it can be stopped with a hammer debounce device (HDD), although there are many on the market that do not work in real life.
2) Yes.
2) Don’t know, I have made HDDs only for my BSAs using the principle of JB’s blast tamer. Non electric gaystates have a Harper valve system that eliminates the bounce, something like that could possibly be made for Edguns.
2) What’s Syria?

I’m confused…

My ears told me the OEM shroud was loud. A modified OEM Edgun shroud was half as loud, or less. Neil’s single and double piece shrouds were both quieter, with the one piece shroud being a tad quieter than a fully modified OEM Edgun shroud. I believe Gabe’s OEM shroud had felt added to the lower shroud vent holes, which mine didn’t.

Neil’s two piece CF shroud was hands down quietest, and looked really nice on my .25 Long. Combine a decent baffled shroud with an oversized can on the end, and that’s serious quiet!

I have absolutely no idea WTF those charts indicate in the above posts. The one fact I did pick up on was rkr’s remark “Those clips seem to have at least one hammer bounce opening the firing valve, possibly even two. Killing that would reduce the noise level quite a lot. This brings up TWO important questions:

1) IS there a double hammer strike in the Edguns?
2) Can it be stopped, or tuned out?
2) Are rkr and synopsys “talking in technical tongues” that no one understands, and is not meaningfully interpreted to help us out? :whoop:
2) Is a HDD possible for an Edgun?
2) Should we stay away from Syria, and leave them to slaughter each other in peace…as is their Allah-given right?

quote synopsys:

Rkr, PM me your email address and i’ll send you the AIFF files that I created the waves with…

Done. Those clips seem to have at least one hammer bounce opening the firing valve, possibly even two. Killing that would reduce the noise level quite a lot.

Edit, here’s what a typical hammer bounce in well tuned PCP looks like when recorded with less sensitive microphone:

Upper track is the muzzle blast showing two valve openings while the lower track is the action noise showing 5 hammer bounces (last 3 won’t open the valve).

Here’s two recorded shots from a gun that’s equipped with functional HDD, as you can see the amount of muzzle blast (duration) is greatly reduced:

I added some horizontal lines to show the various levels and what is higher and where.

Rkr, PM me your email address and i’ll send you the AIFF files that I created the waves with…

quote metalman:

What you are saying is not true, good quality meters use weighted metering and read at different pitch levels so they read dbs at different pitches, you might read with it set to A and get 65 dbs and read it set to B and get 75dbs, better meters also have a fast and slow response, if you do not have settings on the meter and just use a phone or cheap meter the readings are not worth squat. I have used cheaper meters and got different readings from them without doing anything or making any changes. I do not put any store in DB readings unless done with high quality equipment in a controlled environment..

The meter Gabe was using has both A & C weighted measuring and SLOW & FAST response times… 😉

Here are the sound waves for each of the sounds… Total length of sound waves is 0.3 seconds, so the horizontal and vertical scales are the same for both waves.

quote synopsys:

quote Hoot:

The OEM shroud measured 69 dB on my meter at 12″ from the microphone.

The carbon fiber shroud measured 67 dB without the LDC attached.

With the LDC attached, the measurement was 65 dB.

Interestingly, the one piece, aluminum shroud by Clague measured 65 dB…but in real life, my ear said it was a tad louder.

Hoot’s readings:

Factory modified= 69 dB
Carbon no can= 67 dB
Carbon w/can= 65 dB
Aluminum= 65 dB

Carbon w/can = aluminum w/out can…

quote meech1456:

Edgun w/ NC one piece shroud – 68 db
Edgun w/ modified OEM shroud – 68 db

Gabe’s reading is a 1dB difference with the factory modified shroud as Hoot got, and 3dB different for the aluminum reading that Hoot got…

Hey Gabe, can you give us a run down of how you set up the meter?

While a meter may not be worth a shit for this, it is showing the relative difference between the various readings taken under the same conditions. If a decibel meter says one sound is louder than another by 5dB (less than 10%) i’m going to have to accept it. It’s like putting a 24 grain pellet in one hand and a 26 grain pellet in the other and trying to determine one is heavier. NOBODY is going to get it right with any real consistency. The scale will tell you which weighs more even if it isn’t telling you the exact weight.

Some people hear higher frequencies as “louder” while other hear lower frequencies as “louder”. Doing the “hey does this sound louder than this” test is like asking a kid which flavor of ice cream is better. Waaay toooo subjective to be accurate.

I have some really nice sound equipment (mixer and microphones) I think I may need to record a few shots from the EdGun and the Cricket and post the waves, decibel meters are not really made for doing this. What we need to see is the shape of the sound and the levels of the various frequencies involved.

Cell phones, video cameras, Radio Shack sound meters, might as well be suing a potato hooked up to a dishwasher. 😆

It would be better is you recorded the shot and then did a spectrum analysis of that. That will show the frequency range where peak noise occurs and make it easier to compare different blasts produced by different silencers/shrouds. As an example a silencer that makes noise peak at high frequency range sounds actually quieter than a silencer that makes similar peak at low frequency range. It also allows averaging several shots over the frequency range making the results more accurate.

In the end you can produce a graph like this making the comparison much more meaningful:

Nasser it appears that Gabe has modified his shroud in a different way to Horace so it is quite possible his shroud is quieter than Horace’s, without hearing it live there is no way I can comment on it. I thought that Horace’s shroud was very loud but he assured me it was quieter than the stock shroud, if that is so the stock gun must be very loud. You are correct dry firing is louder and I was unable to test with pellets because I thought it was a .22 to begin with and did not have any 25 caliber pellets to test it with. I always like to fire pellets through any shroud or LDC I make to check them for function and accuracy before i ship them, this step had to be left out with this prototype but I am sure someone else will eventually send me a complete gun with a supply of pellets to make a shroud for, then I can be sure what I make is quieter than the shroud on the gun, which is what I did for Horace, both shrouds were clearly a lot quieter on his gun than his shroud.

Try doing the test again but with dry firing, it will sound louder but just try it.

Viewing 15 replies - 31 through 45 (of 323 total)

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