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Old July 2, 2009, 05:42 PM   #1
comn-cents
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Something I know nothing about, a lil help?

So I’m thinking about getting a suppressor but I'm not sure what kind or what gun to put it on.

I have an HK45 w/threaded brl.
One of my AR's or a 22/45 or a 10/22

So do you have to use subsonic ammo to keep it completely quiet?
Do i want wet or dry? Does it matter?

Do i go to any FFL or does it have to be a Class3 dealer to buy one?

If you don't have to use subsonic ammo does the suppresser affect F.P.S.?

Thanks in advance.
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Old July 2, 2009, 07:03 PM   #2
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You must get a Class 3 weapons permit from BATFE. You then must get local LE approval. Here's a link to Wikipedia -

http://en.wikipedia.org/wiki/National_Firearms_Act
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Old July 2, 2009, 07:14 PM   #3
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hey thanks
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Old July 3, 2009, 12:08 AM   #4
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no one with any input? just a little help is all i need.
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Old July 3, 2009, 01:27 AM   #5
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I can't provide info on law but:-
  1. A .22 firing sub-sonic ammo with a silencer will make a "Puut" sound, at about the same level or less as you clapping your hands.
  2. Some semis won't cycle on semi-auto with subsonic ammo.
  3. If you silence a center-fire and use super sonic ammo you will still have flight noise and the super-sonic crack but not the muzzle blast. This means that while you won't be silent, if you are "bombing up" a mob of goats they won't know where you are but will know they are being shot at, giving you some more time to get off a follow up shot.
  4. Get an over-barrel silencer. The main reason for this is that it has two contact points and is harder to knock out of alignment.
  5. The over-barrel silencer will lengthen the barrel. I tended to recommend cutting 2" of the barrel to improve balance.
  6. An over-barrel silencer will affect fps. You will generally gain velocity (due to free-bore boost) and accuracy.
  7. Due to action noise you won't get them silent. If you do use the 10/22 look at something like this to reduce action noise.

Have a look here. It may be cheaper than getting one in the US.

Here in NZ anyone can buy a silencer and as a consequence we silence almost anything. The shop I have linked to had an 870 with a full over-barrel silencer.(Note: I did used to work for them but now have no affiliation with them. I just referenced them as they are Australasia's biggest firearms retailer.)
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Old July 3, 2009, 03:30 AM   #6
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Falcon5NZ:
Quote:
An over-barrel silencer will affect fps. You will generally gain velocity (due to free-bore) and accuracy.
Free bore is at the other end of the barrel, the chamber end. It usually increases velocity, but accuracy is gun-to-gun.

There's nothing in your list about running free bore out at the chamber end. Is that what you mean?
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Old July 3, 2009, 04:07 AM   #7
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I've always heard the reason given for the velocity increase as freebore boost.

To quote Robbie Tiffen (Canterbury Gunsmith and Suppressor Manufacturer)

Quote:
There is also the velocity phenomenon known as "freebore boost". To explain: When a fired projectile uncorks from a rifle bore, the gas expands and dissipates into the atmosphere, causing the blast that we are familiar with. When a suppressor is fitted, the projectile uncorks inside the body of the suppressor and gas continues to work against the base of the projectile, increasing velocity slightly until the projectile exits the suppressor front cap.
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Old July 3, 2009, 04:58 AM   #8
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Quote:
Have a look here. It may be cheaper than getting one in the US.
You cannot order a suppressor from NZ and have it sent to the US, that is illegal unless you are an importer with an SOT.

Quote:
You must get a Class 3 weapons permit from BATFE. You then must get local LE approval. Here's a link to Wikipedia -
That is not exactly accurate. What you do is find yourself a local class 3 (03 SOT) dealer in firearms that has an SOT. There are a few in my area, all you have to do is look around. (Spike's Tactical and Universal Weapons are closest to me)

When you go there, you buy the suppressor, and the dealer will help you in filling out a Form 4. You send in the form (which may require a signature from your local top cop, picture, and fingerprints- see below) along with $200, to the department of loud noises. You wait several months, and they send it back to you with a tax stamp on it. You may then take that form back to the dealer and pick up your item. The form is not a permit per se, but proof that you have registered and paid the tax on the item.

As far as the fingerprints, picture, and top cop permission slip: You do not need to do this if the item is being purchased by a trust or a corporation (this includes LLC). I went the trust route, and had a lawyer draw one up. That cost me $300, but was worth it IMO.
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Old July 3, 2009, 07:13 AM   #9
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Quote:
There is also the velocity phenomenon known as "freebore boost". To explain: When a fired projectile uncorks from a rifle bore, the gas expands and dissipates into the atmosphere, causing the blast that we are familiar with. When a suppressor is fitted, the projectile uncorks inside the body of the suppressor and gas continues to work against the base of the projectile, increasing velocity slightly until the projectile exits the suppressor front cap.
Well frankly it looks like I can't fault your use of that term, but I will say that Mr Robbie Tiffen (Canterbury Gunsmith and Suppressor Manufacturer), is using a definition of "freebore" that would draw a chuckle from most rifle builders and pursuers of bottle necked cartridge accuracy. They know what freebore is and have dealt with it and argued over it's merits for generations. It is that portion of the chamber beyond the end of the cartridge mouth, but before bore rifling engages the bullet bearing surface.

In any case, I know little about suppressors, so there may be jargon there with which I am unfamiliar.

Normally, any expanding gases that "chase" the bullet out the muzzle will impede accuracy as a general rule. The gases are moving at a much, much higher velocity than the bullet and do not stay in a nice neat column of pressure once free of the confines of the rifled bore. Once free of the rifling, any pressure buildup is relieved and great turbulence ensues. There is the reason for a suppressor. Unless a suppressor has a gas-seal tight bore of it's own, the behavior of these very hot, expanding gases can upset the flight of the bullet at the very beginning of it's flight. Bleeding this pressure off, in order to suppress the report, seems contrary to the claim of increased velocities too.

There may be much to learn here, but it seems a strange claim to make.
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Old July 3, 2009, 08:44 AM   #10
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thanks guys.
How about the wet to dry thing?
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Old July 3, 2009, 09:01 AM   #11
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I would imagine the folks in the NFA section would be rhe best ones able to help....you might post these questions there
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Old July 3, 2009, 09:33 AM   #12
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Y'know, I'll just move it there. Thanks for the reminder, oneounceload.
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Old July 3, 2009, 12:08 PM   #13
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Thanks Bud
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Old July 4, 2009, 07:44 PM   #14
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No one will to tell thier suppressor secrets!
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Old July 4, 2009, 09:18 PM   #15
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Quote:
You must get a Class 3 weapons permit from BATFE. You then must get local LE approval. Here's a link to Wikipedia -

http://en.wikipedia.org/wiki/National_Firearms_Act
There is no such thing as a class 3 weapons permit. In the USA small arms are either title 2 (machine guns, silencers, SBS, SBR, DD, AOW) or title 1 (everything else). Class 3 refers to an FFL that has paid the Special Occupational tax class 3 to deal in title 2 weapons. It even says this in the link you posted.

All I need to make or buy a silencer is the ATF form 1 or 4, 5220.20 fingerprints and photos and a $200 check. The ATF form 1/4 is not a permit or a license, it is just proof the tax was paid. It is easier but more time consuming than getting a first time driver's license.

Ranb

Opps, I see divemedic has already addressed this.
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Old July 4, 2009, 09:30 PM   #16
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You might want to start out with a 22lr silencer, they are cheaper and the least noisy; so if you decide that you do not like the performance, then you are out less money. Your profile says you are in the Pac NW. I hope you are not in WA, they allow ownership but use is a gross misdemeanor. ATF form 4 approval is routine and granted as long as the forms are filled out correctly, but it takes 3-5 months from what I hear now.

Any firearm shooting potentially lethal ammo can not be completely silenced by any portable silencer. You will always have some muzzle blast noise, bullet flight noise (even when subsonic) and action noise for semi-auto or machine guns. A decent silencer will lower noise by 20-30 decibels; a factor of 100 to 1000 times lower. But do not expect anything less than 115 decibels for rim fire rifles. Expect at least 125 decibels for 9mm and 130 and up for 223 Remington and higher powered rifles. As long as you are less than 140 decibels the impulse noise is hearing safe; as long as you are shooting out in the open. Using subsonic ammo in a suppressed 308 can lower noise by ten times compared to a standard supersonic load. Here is some test data; http://silencertalk.com/results.htm

While silencers that telescope over an un-ported barrel are much sturdier, the extra weight and bulk may not be worth the small gain in suppression. They also keep the barrel from cooling down as fast as an exposed one, so covering the barrel with the can might not be a good idea when shooting rapidly. Some guns with silencers that extend back are used with ported barrels. These barrels vent off some of the gases into the middle or back of the can and can lower the noise level much more. They also reduce bullet velocity, sometimes a great deal.

Adding water (oil, gel, soda) or anything else that evaporates when the hot gun powder gases flow through the silencer will reduce noise. This is caused by the liquids latent heat of vaporization absorbing heat from the gases and lowering pressure. It is a common practice when shooting pistol silencers, especially 45 acp. I have not heard of anyone doing it for high powered suppressed rifles. Using water in an aluminum can accelerates corrosion, especially if it is made form steel and aluminum.

I made silencer for my 458 socom, 300/338/510 whispers that have cover part of the un-ported barrel, while they use subsonic ammo, they do not lower the bullet speed at all. I have noticed very little in “suppressor boost” when clocking loads over my chronograph. I have noticed when I get a baffle strike though. The bullets tumble and rarely hit the target; they also leave dings in the baffles. I was lucky; I could have been picking up pieces of silencer all over the range instead. While I have not noticed any change in accuracy, the point of impact changes greatly on rifles shot past 100 yards. This is due to the increase weight on the barrel changing the way it rises on recoil and the way it whips around when fired.

If you are interested in making your own silencers, it is easy to do on a metal lathe. I learned to use a lathe by making my first silencer for a 300 whisper. I can post drawings if anyone is interested.

Ranb

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Old July 4, 2009, 10:37 PM   #17
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Hey thanks alot. Great info.
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