Silencer with foam

[pyro]

So I heard that you're not allowed to have foam in the silencer because of U.S. toy silencer laws... does this statement have any merit to it? also does the foam actually suppress the noise, and do you have to custom make the foam pice or can you buy it?

[Dannick]

I'll let someone else give you a technical answer, as I a not sure on the exact regulation, but I believe they are not supposed to be foam filled, but you can get away with it. I've bought many suppressors, and several have been foam-filled from the distributor. I don't think they are supposed to be imported or sold with foam inserts, but that's a very hard thing to regulate.

As for the foam actually helping, it actually does change the sound. Of course with an AEG most of your sound comes from the gearbox anyways, so it probably won't be as effective as you may think. On the other hand, it makes a huge difference on gas guns. Gas blowbacks may not benefit that much, but it definitely will lower the sound from the muzzle. Gas non-blowbacks will have the greatest benefit as there is very little noise from moving parts. Springers are sort of in between a GNBB and AEG, as they don't have as many moving (electrical) parts as the AEG, but they do still have the piston slamming forward.

I'd think you would have to make your own foam insert if your current suppressor doesn't have it inside already, as I have never seen just the foam for sale anywhere. I've actually been toying with the idea of using spray foam to fill a suppressor and just leaving a dowel in the center to keep the BB pathway clear. Not sure if it would be effective but it'd be worth a try.

[pyro]

I haven't bought one yet but I have a KWA M4 CQB that is pretty much an upgraded M4A1 atm... so I was wondering if it would be worth getting one with foam rather than a regular one

[vulrath]

The ATF considers foam-filled replica silencers as actual silencers. Dannick, you're correct about that. There's no specific law; the ATF just put out a white paper (the functional equivalent of a presidential executive order, 'cept from the ATF instead of the President) stating that foam-filled replica suppressors are governed under the NFA Title II, Class III just like real silencers.

As to the effectiveness, my upp'd TM VSR GSPEC (150 spring, SHS sears) increases in volume significantly when I remove the silencer. My pretty much fully-upped L96, on the other hand, doesn't make a difference between the two because I stuffed the stock with urethane foam to reduce vibrations. It's quiet all the time. I haven't really done a test with GBBRs and foam-filled silencers because both working GBBRs have positive threads on the barrels, and my only working silencer has negative threads. On my KJW M700, it's scary quiet - without the silencer, it makes a higher-pitched pop (not quite a "crack"), but with it, it makes a dull thud. The best (read: most hilarious) description I can think of, I read on ASF a few years ago - "like the sound of a sack of potatoes hitting a small child, only without the screams of pain."

[pyro]

any experience with AEGs?.. just to get a second opinion (Not that I don't take your word for it or anything,Dannick)

[vulrath]

With AEGs, they'll reduce the sound to a degree, but they won't eliminate the sound entirely, just what which is coming out from the muzzle. In order to do more than that, you'd need to do a specialized build where you would have to cover the outside of the gearbox with car soundproofing material. I believe there was someone that did that to their P90 years ago, and it was stupid quiet.

[thread drift]
As a slight drift, did you know that a real silencer's only purpose is to get rid of that eardrum-shattering crack that a real gun makes when you shoot it? It was designed by a guy in the 1920's so that he could enjoy shooting in his backyard without damaging his hearing or that of his neighbors. That sound you hear silenced weapons make in movies is patently false.
[/thread drift]

[pyro]

great thanks