| | | | | | | | | Silencing my crosman nitro venom. | | | | | |
Posted: Sun Dec 09, 2012 3:19 am |
|
|
biador619 |
New Member |
|
|
Joined: 09 Dec 2012 |
Posts: 5 |
|
|
|
|
Hi. I own a nitro venom dusk. So far I put around thirty rounds through her. I couldn't stand the loud sound from firing off a pellet so I made a muffler. I got a 1/2" PVC pipe and drilled it full of holes, covered it tightly with cotton, inserted it into a 1.5" PVC pipe and put end caps on it. It helped drop the DB from 103 to 91. Not bad but it's still loud. I did some reading and people were saying that the majority of the sound produced from the nitro piston rifle is from the piston itself. So I tested this theory. I tested by shoving the end of the barrel between a thick blanket and guess what....the DB read at only 55 DB. crazy right. There was barely any noise from the actual piston. Now this got me wondering how I can muffle the sound even more. Should I just stick with the current muffler I have now and just replace the cotton with a different type of material? Or should I just use a 1.5" PVC and use baffles? The muffler lol is about 8" already and I don't want it any longer. Any thoughts?[/b] |
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Sun Dec 09, 2012 5:28 am |
|
|
Alstone |
Moderator & Site Supporter |
|
|
Joined: 01 Mar 2007 |
Posts: 4139 |
Location: Linconshire, ENGLAND |
|
|
|
To really get the sound down you need a tube 8” long and 1.5” dia, use large dia washers to split it into four sections, in each section use a hair roller wrapped in a strip of scotch bright pad, this should bring the sound down to around 65-70 db at 10 meters.
The key to mufflers is volume the more the better, just be careful using or owning one in the USA, as their are very draconian penalties’ if you do not have a licence for it.
Al |
|
_________________
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Sun Dec 09, 2012 12:55 pm |
|
|
biador619 |
New Member |
|
|
Joined: 09 Dec 2012 |
Posts: 5 |
|
|
|
|
Alright I'll give this a shot. Does scotchbrite really work better than cotton? Also will making the exit hole of the muffler the smallest size possibly lower the DB much more? Hoping ill be a to drop the DB down to 60db or less. Oh another question will adding more sections lower the DB even more? Thanks |
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Sun Dec 09, 2012 7:06 pm |
|
|
Alstone |
Moderator & Site Supporter |
|
|
Joined: 01 Mar 2007 |
Posts: 4139 |
Location: Linconshire, ENGLAND |
|
|
|
Cotton is to dense and will compress, reducing the exit hole will not make much difference, as you should have reduced the pressure considerably by the time the pellet reaches that point, plus if you cut the clearance down to much it will interfere with the pellet flight.
Increasing the volume makes a lot of difference, increase the tube dia to 2” and length to 9”, and it should be very quiet. You don’t say what cal the rifle is, but a .22 running around 12 flb will be quieter than a .177 at the same power.
Al |
|
_________________
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Sun Dec 09, 2012 7:27 pm |
|
|
biador619 |
New Member |
|
|
Joined: 09 Dec 2012 |
Posts: 5 |
|
|
|
|
Well I tried exactly what you suggested but the DB is still at 90 ish DB. I used scotch brite, hair rollers and a 1.5"x8" PVC. I also used 5 1/2" washers between the segments. This is pretty frustrating :/ is it probably the hight velocity of my .177 7g pellets? Should I go with a heavier pellet to get a slower velocity? |
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Sun Dec 09, 2012 9:28 pm |
|
|
garththomas |
Veteran Member |
|
|
Joined: 12 Jan 2012 |
Posts: 165 |
Location: Ontario, Canada |
|
|
|
Did you have someone else stand back and listen. a lot of the noise comes from the spring action even with a gas spring. |
|
_________________ QB57
Backyard Sweeper |
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Sun Dec 09, 2012 9:45 pm |
|
|
biador619 |
New Member |
|
|
Joined: 09 Dec 2012 |
Posts: 5 |
|
|
|
|
No I didn't didn't have anyone with me. The nitro piston itself just make a tiny thump. All the noise is being generated at the muzzle. I'll post another update once I do some test shots with a heavier pellet. |
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Sun Dec 09, 2012 10:41 pm |
|
|
toadmyster223 |
Senior Member |
|
|
Joined: 20 Mar 2012 |
Posts: 501 |
Location: Fayette Nam, PA |
|
|
|
Your pellets aren't going fast enough to crack a sonic boom, are they? I haven't shot a Nitro 177, I don't know if they will do that with standard ammo. If you're using special Gamo gold ammo or something, I'd stop |
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Sun Dec 09, 2012 11:46 pm |
|
|
biador619 |
New Member |
|
|
Joined: 09 Dec 2012 |
Posts: 5 |
|
|
|
|
For now I'm just using the crosman premier hollow points @7.9g I just going by, the heavier pellet the harder the impact along with lower velocity. And with lower velocity I'm hoping the sound at the end of the barrel will be much less. I think it's the only option left unless I cans find a better way to build a muffler. I don't think I'm breaking the sound barrier but I think the exiting pressure of 900-1000 FPS will still create a lot of noise. |
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Mon Dec 10, 2012 4:20 am |
|
|
Alstone |
Moderator & Site Supporter |
|
|
Joined: 01 Mar 2007 |
Posts: 4139 |
Location: Linconshire, ENGLAND |
|
|
|
The hole in the washers you are using to divide the chambers up need to have around a 5.5-6mm hole, the chambers should be divided with the first being one third of the muffler length, and the rest equally spread over the remaining length.
To secure the baffles make them a good fit in the outer tube and use a smaller tube sections between to hold them in place, a good seal and solid construction makes a lot of difference, and all joints being gas tight.
Al |
|
_________________
|
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Mon Dec 10, 2012 8:10 am |
|
|
radar |
Silver Status Member |
|
|
Joined: 13 Nov 2011 |
Posts: 1138 |
Location: Des Moines, Iowa, USA |
|
|
|
Alstone wrote: |
...just be careful using or owning one in the USA, as their are very draconian penalties’ if you do not have a licence for it.
Al |
True that, but looking at the ATF website, and especially their definitions section, I could not find anything that limits silencers for airguns. You might be OK there.
Of course...(1) a prosecuter might claim it can be transferred to a firearm, (2) I missed or misread something, so check it out yourself, (3) there are state or local laws prohibiting silencers on airguns or ownership at all. |
|
_________________ It's never too late to have a happy childhood. |
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Mon Dec 10, 2012 11:33 am |
|
|
Slavia |
Moderator |
|
|
Joined: 31 Mar 2008 |
Posts: 4382 |
Location: Waseca, Minnesota, USA |
|
|
|
Quote: |
a prosecuter might claim it can be transferred to a firearm |
That's the key, and it sounds like your construction could allow it to be transferred to a firearm. Research the subject very carefully before you proceed - starting with this link:
http://www.airgunhome.com/pages/silencers.html |
|
_________________ ¡Listo! ¡Apunte! ¡Fuego! |
|
|
|
|
|
| | | | | | | | |
| | | | | | | | | | | | | | |
Posted: Tue Dec 11, 2012 2:38 pm |
|
|
Mark5043 |
Silver Status Member |
|
|
Joined: 12 Apr 2009 |
Posts: 1379 |
|
|
|
|
radar wrote: |
Alstone wrote: |
...just be careful using or owning one in the USA, as their are very draconian penalties’ if you do not have a licence for it.
Al |
True that, but looking at the ATF website, and especially their definitions section, I could not find anything that limits silencers for airguns. You might be OK there.
Of course...(1) a prosecuter might claim it can be transferred to a firearm, (2) I missed or misread something, so check it out yourself, (3) there are state or local laws prohibiting silencers on airguns or ownership at all.
|
If the device can be removed from an air gun,and attached to a firearm,and it lowers the report by even 1db,and does so even for only one shot,before being destroyed..then that device technically is a firearm "just by itself"...Thus it requires a serial number,and the proper paperwork filled out with the ATF. Remember the key point here..If the device is tested,and meets the requirements stated,then that device IS a firearm,under Federal Definition. Doesn't matter what you put the device on..air gun,or not. |
|
_________________
|
|
|
|
|
|
| | | | | | | | |
Note: If you are seeing "Please enter your username and password to log in." Your browser cookies have been reset
or you need to register to access the topic in question. Use the 'Register' button near the top left of this page.
|