Vented Shroud to Reduce Noise

DIY Modifications to the Benjamin Marauder, like Depingers, bolt handles, etc.
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Vented Shroud to Reduce Noise

Postby steveinla on Fri Apr 23, 2010 9:14 pm

Hi Guys,
Has anyone vented the shroud? My AA S410 has three 5/32" holes at 9, 12, and 3 O'Clock at the rear of the shroud. My friend tells me that his Edgun has many, (9-12), tiny holes drilled in the rear of the shroud. Has anyone tried this with the Marauder? I am wondering if a series of small holes drilled around the circumference of the shroud combined with some Mr. Clean melamine foam just in front of those holes might help to reduce sound levels. My .25 Marauder expends alot of air for each shot and I am trying to dissipate it as efficiently as possible.
Steve
p.s. ShootingChrony Inc. is a terrible company to deal with. Buy a Pro Chrono by Competition Electronics...they're made in the U.S.A.
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Re: Vented Shroud to Reduce Noise

Postby Supercharged86 on Sat Apr 24, 2010 5:44 pm

Steve, When you say "rear" of the shroud, are you saying the holes are at the breech end? Does AirArms incorporate baffles like Crosman? Much like a vented shotgun barrel, this may have some potential. However, any "vented" hole incorporated into the end of the shroud would also have to exist in the forward most baffle. I don't see any reason why this wouldn't work. Nice idea :D . So how many holes :?: Steve
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Re: Vented Shroud to Reduce Noise

Postby Vakeiros on Sat Apr 24, 2010 7:05 pm

i've a S410 and forget it. it won't work on marauder because the end of the barrel has a piece that isolates the "silencer" from the rest of the shroud, while the s410 only have the shroud covering the barrel, so the holes on marauder ont work because no air will pass through them while on S410 some air get out from the rear of the shroud,

i don't know if i made myself clear, i can insert some pictures.

regards
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Re: Vented Shroud to Reduce Noise

Postby dogwood on Sun Apr 25, 2010 8:49 pm

actually it will work with the marauder, the portion on the end of the barrel that the baffles rest on is vented as well, so air will travel down the shroud, wouldn't work near as well if it wasn't
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Re: Vented Shroud to Reduce Noise

Postby steveinla on Sun May 02, 2010 4:16 pm

I drilled some holes, 13, 1/16" holes, 1 1/4" in front of the receiver,(there is a flange that extends 1" beyond the receiver that the shroud screws onto). It got louder back by the shooter. I'm not sure that this helped...so I don't recommend it. There is a tremendous amount/volume of air being released for each .25 caliber shot and the holes definitely release lots of it. As far as deadening the sound goes, I'm still evaluating it. I have wrapped tape around the holes until I can do some more testing. It still shoots very accurately and I am very pleased with it.
Steve
p.s. ShootingChrony Inc. is a terrible company to deal with. Buy a Pro Chrono by Competition Electronics...they're made in the U.S.A.
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Re: Vented Shroud to Reduce Noise

Postby Supercharged86 on Sun May 02, 2010 5:39 pm

I'm thinking if all the holes were placed at the end, say within the last baffle (and through the baffle, so the holes line up), just like a vented shotgun barrel, might be best. :D
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Re: Vented Shroud to Reduce Noise

Postby dogwood on Sun May 02, 2010 9:38 pm

steveinla wrote: It got louder back by the shooter. I'm not sure that this helped...so I don't recommend it.


try putting some of that magic foam, or even scotch brite where the new holes are, you want to slow down the air flow a bit.
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Re: Vented Shroud to Reduce Noise

Postby Supercharged86 on Mon May 03, 2010 10:51 am

steveinla wrote:I drilled some holes, 13, 1/16" holes, 1 1/4" in front of the receiver,(there is a flange that extends 1" beyond the receiver that the shroud screws onto). It got louder back by the shooter. I'm not sure that this helped...so I don't recommend it. There is a tremendous amount/volume of air being released for each .25 caliber shot and the holes definitely release lots of it. As far as deadening the sound goes, I'm still evaluating it. I have wrapped tape around the holes until I can do some more testing. It still shoots very accurately and I am very pleased with it.


Sort of surprised this would happen, given that part #27 along with o-ring #34 are attached to the end of the barrel, sealing the shroud. It would appear that there wouldbe nearly zero air flow being directed backward because of these parts, NO?
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Re: Vented Shroud to Reduce Noise

Postby dogwood on Mon May 03, 2010 3:56 pm

Steve, if you look at part 27 you'll notice that there are a number of vent holes between where the barrel ends and the O-ring, that allows air to expand back into the rest of the shroud, trust me, the shroud wouldn't be nearly as effective if is didn't.
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Re: Vented Shroud to Reduce Noise

Postby Supercharged86 on Mon May 03, 2010 5:00 pm

dogwood wrote:Steve, if you look at part 27 you'll notice that there are a number of vent holes between where the barrel ends and the O-ring, that allows air to expand back into the rest of the shroud, trust me, the shroud wouldn't be nearly as effective if is didn't.


Oh, didn't see that. sorry. thanks D
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