.22 Vulcan TGAG shroud
Couple of months ago if you asked me if I was going to buy a Vulcan or Mutant my answer was no. I was happy with my .22 Cricket and .25 R3M. But since I have no life and I hang out with old folks on here, I was constantly exposed to the Mutant and Vulcans. Mutant appealed to me because of how quiet the report was and the smoothness in the cocking. Very similar to the Cricket and that’s why I held out so long. Tell you the truth the Mutant compact is a very nice and quiet gun. I prefer it over my Cricket based on the weight and compactness. Then comes the Vulcan, I had a prod sitting around that was never going to get used again because of the mutant and I had other airgun accessories laying around. You guys probably saw a bunch of my ads on the Yellow. Any hoot, I was able to gather enough money to buy a Vulcan. Oak man hooked me up real nice on a used one with all the bells and whistles. He said it was too loud for his shooting even though it has the latest TGAG shroud. It baffled me so I took a chance on it. Ernest had already worked his magic and got rid of the twang and ping. But here is the thing, the gun screamed like a hungry fat lady. Oak wasn’t kidding when he said the gun was still loud. It rang my ears for a long time and this is only after a few shots. Really bummed out, I kept thinking how is this shroud so loud? I don’t own a hummingbird but others have compared this new shroud to it. Very tempted to sell it to another member on here, I gave it one last chance and made my own shroud for it. After seeing jfrazier30’s video(http://talonairgun.com/forum/viewtopic.php?f=54&t=33399) of how quiet his gun is I was determined to get mine to that level. He’s also shooting out of a TGAG shroud but mine doesn’t sound anything like it.
I spent a few hrs in the garage and made my own shroud. Crossed my fingers, closed my eyes and pulled the trigger. The sound was night and day! Exactly like jfrazier’s. Told Vince I am sorry but I can’t sell this gun anymore, it sounds awesome. Just hammer slap and hardly any muzzle blast. This shooting without LDC. With LDC, forget about it, super quiet. When guys say there is no hammer slap, they are lying, when metal slaps on metal there’s going to be a hammer slap. However, there is no ping. Just a quick slap.
Here is what the TGAG shroud looks like inside
Everything looks like it was CNC very nicely and the baffle holes are very tight to the .22 pellet.
Here is what is in my shroud, just two baffles, two metal curlers wrapped in felt and spacers
My shroud has 4 vent holes in a line at the top.
Also topped off with a black delrin cap.
For this one, I mad an LDC without the cone shape in the back to make it short as possible
I am very happy with this gun now but still trying to figure out why the TGAG is so loud. Any suggestions? Do I have to align the holes in the side of the baffles so that they are all in a line?
All Replies
I’m making this as simple as I know how!
There is only ONE way to quiet a pcp. You must reduce the air pressure exiting the muzzle. How? There are only two physically possible ways. One is to disrupt the air flow with baffles and cause it to leave the muzzle in a long column instead of one short hard blast. The second method is to physically reduce the amount of air the baffles must deal with, and that is to vent the air to the outside before it hits the muzzle. That’s it. No genius involved…just a simple look at the physics of the problem. Now, I will tell you how…
1) Vulcan baffles have a tiny O ring at the top and bottom of each baffle…and I’m not talking about the big O ring between each baffle. That’s right…look for yourself. Since each baffle has two holes in it, air is released into that small dead air space between those two tiny O rings and the shroud tube. It works. Want to make it work better, say MUCH better? Carefully measure where the middle of each baffle will be, when in place, and drill a small hole into each side of the shroud where the middle of each baffle rests, so that trapped air between those two tiny O rings can escape to the outside. The hole should not be larger than 1/16th inch. You can go larger…slightly. AND, put one on each side of the shroud. NO…the holes in the baffle sides do not have to line up with the tiny shroud vent holes. The air doesn’t care where those holes are located. It will find its way out just fine. That way, each successive baffle has less air pressure to deal with.
Note these tiny baffle O rings, and you have to look close to see them, prevent gross baffle metal to shroud metal contact, and what little metal contact that does take place is muffled by the large O rings between each baffle. That’s one big difference I saw in the TGAG baffles and the OEM baffles.
2) Now the simple part. You have vented each baffle at the muzzle end of the shroud and that reduces air volume, pressure, vibration, and prolongs the exhaust time of the muzzle blast…that alone quiets the gun down. BUT…you need more, much more. You can do as I have preached again and again…put eight (8) holes at the base of the shroud, about an inch to an inch and one-half up from the breech. You can put them in a circle around the shroud, or you can put them in a straight line at the bottom of the shroud. How do you keep the shroud from rotating and showing those eight holes at the bottom in a straight line? Easy…buy an O ring slightly smaller than the shroud and put it over the barrel so the shroud compresses it against the breech when you screw the shroud on. The forward pressure of that compressed O ring will hold that shroud in place quite nicely, and those holes stay out of sight.
This being done, you have reduced air volume/pressure exiting the muzzle at 16 to 20 points along the shroud length, depending on how many holes you use. (I only did four along each side of the shroud, along side each baffle. I skipped venting one baffle…looks better. )
Now, if you need Really Quiet, buy a DonnyFL LDC for the front of your shroud. John Hagan makes an adapter for Vulcan shrouds.
At this point I defy you to make the Vulcan .25 any quieter without lowering FPS. I run mine at 50 FPE because that’s what I want out of a .25 caliber! Do this to a Vulcan .22 and you could shoot the damn thing next to your sleeping wife and not wake her up!
I’m waiting for my Ernest Delrin spring holder-thingee to reduce the ping/slap, then that’s about as much as I know to do at this time.
Kind regards,
Uncle Hoot:
from the perspective of simple Physics, I think this makes a lot of sense here.
I agree with Uncle Hoot.
Uncle :hoot: left out two things. First is the air blast hitting the walls of the shroud/silencer. That will make noise unless dampened down. Methods are felt or other dampening material held against those walls and using material that doesn’t make much noise for construction (carbon fiber). The other one is the exit hole of the silencer. A big hole will reduce the air speed and move the dB peak to low frequency while a small one will have high speed and dB peak in higher but still audible frequency. If you can easily manufacture a new end cap, try drilling the exit hole to 9mm diameter and you might get surprised.
Dear Off-yer-rkr,
There are two schools of thought at play here…
1) The smaller the pellet holes in the baffles, the more effective the baffles will be at slowing the air pushing it’s way through towards the path of least resistance: the muzzle. Slowing air is but one effect, another is disruption of the harmonics of the air charge as it explodes out of the barrel’s muzzle.
2) The tighter the shroud’s muzzle, the more back-pressure is developed against the exploding air release from the barrel’s muzzle. (…and the air exiting a rifle muzzle is indeed “exploding”, an undisrupted expansion of gas…thus the loud report) This back-pressure results in more air being forced into the empty shroud behind the baffles. That’s very important because it delays the exit of the initial explosive air charge, forcing the propelling air charge to expand/slow when it enters the un-baffled shroud behind the baffles, thus permitting that air to be “re-baffled”, slowed yet further, before it finally exits the shroud’s muzzle.
With respect for your opinion, under certain circumstances not involving baffles/enclosed shrouds, you are very correct…a small orifice is much louder than a larger orifice, but that only applies to un-baffled air. There must be sufficient “back-pressure” to permit baffles to perform their primary task of slowing air exhaust by disrupting it’s escape path, and permitting it’s expansion within the empty shroud tube. Without back pressure, baffles cease to work. That requires extremely tight tolerances of the baffle/shroud muzzle’s bore.
Hoot:
The clue here is to combine those two things. We want to use small diameter baffle holes inside the shroud and then tune the noise by altering the exit hole size. Small hole usually makes higher dB peak at higher frequency, for some of us that actually sounds less disturbing than a lower peak at low frequency.
If we are talking about silencers where back venting is not possible, then the baffle hole size inside the unit is not that important. In my tests 1.5mm bigger holes in the baffles inside (.177 gun – going from 5mm to 6.5mm) made no measurable difference. However, with controlled venting of those silencer chambers through the silencer mantle (Hugget being good example) we can achieve very good results. What I haven’t tried yet is combining that controlled venting to the latter chambers of a shroud – which is basically the same thing uncle :hoot: suggested. The difference is in technique of doing it, Hugget uses HW style internals with mesh and felt to control the amount of air getting out. Then again when we’ve done all those other mods, then the hammer hitting the valve stem is usually the annoying thing.
Rumor has it that Hoot fucked Oakley by sending him a low quality Air Arms fill probe with the EDgun he bought from Hoot. Oakley passed the bad penny fill probe onto Donny. So fellow TAG members be on the lookout for shitty fill probes that may come from Florida.
Poor Oak could not make rent again. Had to sell one of his guns.
Sent from my Z30 using Tapatalk
As Donnie whined all day yesterday about how loud my Vulcan was I offered to give him his money back ungrateful pencil neck airgun geek.
What fill probe. By the way you have to change your signature an add my Vulcan.
Cry me a river Oakey Dopey, not my fault you gave up on this gun and sold it for pennies to me lol. Sucker! BtW still waiting on the fill probe.
I’m making this as simple as I know how!
There is only ONE way to quiet a pcp. You must reduce the air pressure exiting the muzzle. How? There are only two physically possible ways. One is to disrupt the air flow with baffles and cause it to leave the muzzle in a long column instead of one short hard blast. The second method is to physically reduce the amount of air the baffles must deal with, and that is to vent the air to the outside before it hits the muzzle. That’s it. No genius involved…just a simple look at the physics of the problem. Now, I will tell you how…
1) Vulcan baffles have a tiny O ring at the top and bottom of each baffle…and I’m not talking about the big O ring between each baffle. That’s right…look for yourself. Since each baffle has two holes in it, air is released into that small dead air space between those two tiny O rings and the shroud tube. It works. Want to make it work better, say MUCH better? Carefully measure where the middle of each baffle will be, when in place, and drill a small hole into each side of the shroud where the middle of each baffle rests, so that trapped air between those two tiny O rings can escape to the outside. The hole should not be larger than 1/16th inch. You can go larger…slightly. AND, put one on each side of the shroud. NO…the holes in the baffle sides do not have to line up with the tiny shroud vent holes. The air doesn’t care where those holes are located. It will find its way out just fine. That way, each successive baffle has less air pressure to deal with.
Note these tiny baffle O rings, and you have to look close to see them, prevent gross baffle metal to shroud metal contact, and what little metal contact that does take place is muffled by the large O rings between each baffle. That’s one big difference I saw in the TGAG baffles and the OEM baffles.
2) Now the simple part. You have vented each baffle at the muzzle end of the shroud and that reduces air volume, pressure, vibration, and prolongs the exhaust time of the muzzle blast…that alone quiets the gun down. BUT…you need more, much more. You can do as I have preached again and again…put eight (8) holes at the base of the shroud, about an inch to an inch and one-half up from the breech. You can put them in a circle around the shroud, or you can put them in a straight line at the bottom of the shroud. How do you keep the shroud from rotating and showing those eight holes at the bottom in a straight line? Easy…buy an O ring slightly smaller than the shroud and put it over the barrel so the shroud compresses it against the breech when you screw the shroud on. The forward pressure of that compressed O ring will hold that shroud in place quite nicely, and those holes stay out of sight.
This being done, you have reduced air volume/pressure exiting the muzzle at 16 to 20 points along the shroud length, depending on how many holes you use. (I only did four along each side of the shroud, along side each baffle. I skipped venting one baffle…looks better. )
Now, if you need Really Quiet, buy a DonnyFL LDC for the front of your shroud. John Hagan makes an adapter for Vulcan shrouds, or tell Donny to put threads in the cone at the bottom of his LDC to match the Vulcan threads.
At this point I defy you to make the Vulcan .25 any quieter without lowering FPS. I run mine at 50 FPE because that’s what I want out of a .25 caliber! Do this to a Vulcan .22 and you could shoot the damn thing next to your sleeping wife and not wake her up!
I’m waiting for my Ernest Delrin spring holder-thingee to reduce the ping/slap, then that’s about as much as I know to do at this time.
Kind regards,
Uncle Hoot:
Thank you I will be trying this.
Keep up the great work Donny!
Uncle :hoot: left out two things. First is the air blast hitting the walls of the shroud/silencer. That will make noise unless dampened down. Methods are felt or other dampening material held against those walls and using material that doesn’t make much noise for construction (carbon fiber). The other one is the exit hole of the silencer. A big hole will reduce the air speed and move the dB peak to low frequency while a small one will have high speed and dB peak in higher but still audible frequency. If you can easily manufacture a new end cap, try drilling the exit hole to 9mm diameter and you might get surprised.
Dear Off-yer-rkr,
There are two schools of thought at play here…
1) The smaller the pellet holes in the baffles, the more effective the baffles will be at slowing the air pushing it’s way through towards the path of least resistance: the muzzle. Slowing air is but one effect, another is disruption of the harmonics of the air charge as it explodes out of the barrel’s muzzle.
2) The tighter the shroud’s muzzle, the more back-pressure is developed against the exploding air release from the barrel’s muzzle. (…and the air exiting a rifle muzzle is indeed “exploding”, an undisrupted expansion of gas…thus the loud report) This back-pressure results in more air being forced into the empty shroud behind the baffles. That’s very important because it delays the exit of the initial explosive air charge, forcing the propelling air charge to expand/slow when it enters the un-baffled shroud behind the baffles, thus permitting that air to be “re-baffled”, slowed yet further, before it finally exits the shroud’s muzzle.
With respect for your opinion, under certain circumstances not involving baffles/enclosed shrouds, you are very correct…a small orifice is much louder than a larger orifice, but that only applies to un-baffled air. There must be sufficient “back-pressure” to permit baffles to perform their primary task of slowing air exhaust by disrupting it’s escape path, and permitting it’s expansion within the empty shroud tube. Without back pressure, baffles cease to work. That requires extremely tight tolerances of the baffle/shroud muzzle’s bore.
Hoot:
Looks like Donny found the joys of Weichrauch style silencers. They are very good and simple designs.
Uncle :hoot: left out two things. First is the air blast hitting the walls of the shroud/silencer. That will make noise unless dampened down. Methods are felt or other dampening material held against those walls and using material that doesn’t make much noise for construction (carbon fiber). The other one is the exit hole of the silencer. A big hole will reduce the air speed and move the dB peak to low frequency while a small one will have high speed and dB peak in higher but still audible frequency. If you can easily manufacture a new end cap, try drilling the exit hole to 9mm diameter and you might get surprised.
Results may differ based on what you have done to your gun.
My gun’s spec are as follows:
-905 fps
-Ernest added two depingers in the air tube
-longer spring guide
-replaced brass bushing with delrin (Ernest)
Sorry for shakiness. Iphone was place right on the side of the gun
First one is my carbon fiber shroud only:
Shroud and LDC
Can’t see the links. Could you please post videos again?
Sent from my iPad using Tapatalk
:hoot:
I’m making this as simple as I know how!
There is only ONE way to quiet a pcp. You must reduce the air pressure exiting the muzzle. How? There are only two physically possible ways. One is to disrupt the air flow with baffles and cause it to leave the muzzle in a long column instead of one short hard blast. The second method is to physically reduce the amount of air the baffles must deal with, and that is to vent the air to the outside before it hits the muzzle. That’s it. No genius involved…just a simple look at the physics of the problem. Now, I will tell you how…
1) Vulcan baffles have a tiny O ring at the top and bottom of each baffle…and I’m not talking about the big O ring between each baffle. That’s right…look for yourself. Since each baffle has two holes in it, air is released into that small dead air space between those two tiny O rings and the shroud tube. It works. Want to make it work better, say MUCH better? Carefully measure where the middle of each baffle will be, when in place, and drill a small hole into each side of the shroud where the middle of each baffle rests, so that trapped air between those two tiny O rings can escape to the outside. The hole should not be larger than 1/16th inch. You can go larger…slightly. AND, put one on each side of the shroud. NO…the holes in the baffle sides do not have to line up with the tiny shroud vent holes. The air doesn’t care where those holes are located. It will find its way out just fine. That way, each successive baffle has less air pressure to deal with.
Note these tiny baffle O rings, and you have to look close to see them, prevent gross baffle metal to shroud metal contact, and what little metal contact that does take place is muffled by the large O rings between each baffle. That’s one big difference I saw in the TGAG baffles and the OEM baffles.
2) Now the simple part. You have vented each baffle at the muzzle end of the shroud and that reduces air volume, pressure, vibration, and prolongs the exhaust time of the muzzle blast…that alone quiets the gun down. BUT…you need more, much more. You can do as I have preached again and again…put eight (8) holes at the base of the shroud, about an inch to an inch and one-half up from the breech. You can put them in a circle around the shroud, or you can put them in a straight line at the bottom of the shroud. How do you keep the shroud from rotating and showing those eight holes at the bottom in a straight line? Easy…buy an O ring slightly smaller than the shroud and put it over the barrel so the shroud compresses it against the breech when you screw the shroud on. The forward pressure of that compressed O ring will hold that shroud in place quite nicely, and those holes stay out of sight.
This being done, you have reduced air volume/pressure exiting the muzzle at 16 to 20 points along the shroud length, depending on how many holes you use. (I only did four along each side of the shroud, along side each baffle. I skipped venting one baffle…looks better. )
Now, if you need Really Quiet, buy a DonnyFL LDC for the front of your shroud. John Hagan makes an adapter for Vulcan shrouds.
At this point I defy you to make the Vulcan .25 any quieter without lowering FPS. I run mine at 50 FPE because that’s what I want out of a .25 caliber! Do this to a Vulcan .22 and you could shoot the damn thing next to your sleeping wife and not wake her up!
I’m waiting for my Ernest Delrin spring holder-thingee to reduce the ping/slap, then that’s about as much as I know to do at this time.
Kind regards,
Uncle Hoot:
Ernest, I bet Donny’s wife will disagree…….. 😆
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Some old measurements I found:
Stock HW vs. one with first chamber vented with 6*4mm holes. When I used 6mm felt layer instead of 3mm the sound level dropped below the stock HW unit.
Couldn’t find the silencer exit hole test though 🙁