I am proposing a thread that will hopefully have 'tack' potential.  Many of the same questions get asked over and over by people who come and go through here.

I was thinking that this could be both a 'technical discussion/explanation' as well as a type of 'buyers guide'.  Not by brand name, but by features to look for when making the purchase.

I must admit I know very little about suppressed weaponry, only that it would have saved a better portion of my hearing in real world gun fights in the past.  So I am counting on people in the 'industry' to make some excellent posts that I'll be able to reorganize her in a logical format.

I'll start with some of the technical questions people ask:

Are they legal? How do I buy one?
For the most part yes, however some states do not allow certain NFA items.  Federally you must meet the following requirements: Be at least 21 years of age, be a U.S. citizen, have no felony convictions or domestic violence convictions, have no dishonorable discharge, not deemed mentally unstable by a competent authority.  Basically the same rules for owning a handgun.  The NFA rules/laws are posted through the BATFE website.

There is one caveat to this.....one member applied for and was approved to "manufacturer" his own SBR from a legally possessed AR15 when he was 18.  If you made your own suppressor with a FORM 1 I suppose you could apply the same ruling.  But as we know the ATF changes their mind like they do their underwear. ETA: you have to be 21 to buy one from a dealer, but you can buy one from an individual or entity at 18, as well as make your own at 18.

At this time, the following states allow private ownership of silencers:
AK, AL, AR, AZ, CO, CT, FL, GA, IA, ID, IN, KS, KY, LA, MD, ME, MI, MN, MS, MT, NE, NV, NH, NM, NC, OH, OK, OR, PA, SC, SD, TN, TX, UT, VA, VT, WA, WV, WI, and WY. Of the eight states which do not allow civilian ownership, CA and MA allow class 3 dealers and class two manufacturers to possess silencers.



How does a suppressor/silencer work?
Suppressors, also called silencers or 'cans', work very much like a car muffler.  They reroute the exiting gases to allow them to more slowly expand, thus creating more of a 'hissss' than a 'pop'.  Think of a soda can.  When you open the top very quickly you get a 'pop' sound.  If you slowly break open the seal you get a quieter 'hissssssss'.  This is basically the same principle (except the gases in the firearm combust causing a small "explosion" if you will).  The idea is to reduce the rate that these hot gases hit the outside oxygen and thereby reduces the "burn" effect.  You could actually get the same effect (although not as great) by creating a super long barrel.  I believe there is a shotgun barrel that adds an additional 30" to a regular skeet/trap barrel with several gas ports along the top.  In effect it allows the gases to burn more completely before exiting and also allows the gas to escape along the many "compensation ports".

Can any firearm be suppressed?
Well, that answer is relative.  I could technically suppress a revolver and reduce the amount of gas and noise coming from the barrel, but the amount of gas and noise that emits from the cylinder gap makes this a fruitless endeavor.  People seem to always pose the question about suppressing a shotgun as well.  Again, technically you could build a suppressor for one but it would be so large and cumbersome it would have no "tactical" advantage or usefulness.  You also run into the problem of only shooting slugs (to prevent massive baffle strike by the buckshot pellets) or coming up with some type of multi-ported interior barrel inside the suppressor.

Barrel length also plays a HUGE part of suppressor effectiveness.  Remember that the shorter the barrel the less complete the gases burn causing a greater "combustion" outside the muzzle. When these unburnt gases hit the first 'chamber' of the suppressor the more it heats of the can.  The more it heats it up the less effective it becomes.  There is also the greater chance of wear/damage to the suppressor with the super high temps and pressure (think of a 'plasma cutter' )  

Generally, most pistol suppressors can handle the temps of any standard size pistols.  Although reliable cycling of the weapon becomes an issue depending on the design of the action.  AR style carbines/rifles are best suited for barrels longer than 11.5".  Some manufactures will not warranty their products on the "short barrels" such as 7.5" and 10.5" due to the problems that can result from them.  I have no experience with these types of setups (although I'm saving up for one in the near future!)

Can I use any ammo or do I have to buy special ammo?

Depends on what you're after.  Any ammo that is super-sonic (faster than the speed of sound) will create it's own "sonic crack" and be impossible to 'silence' so to speak.  For center fire rifles you can buy subsonic rounds to eliminate most of the noise.  Remeber too that the sound of the action on a semi-auto can be very loud as well.  Some subsonic ammo will not reliably function the action of the AR15 setup.  For pistols (.45ACP in particular) alot of the standard ammo is already 'sub-sonic'.

Do I have to do anything special to my firearm to accept a suppressor?

Most firearms will need to be threaded for a suppressor.  Even those barrels that are already threaded (AR15's) should be rethreaded when attaching a suppressor.  THis is because that in high volume production, the threads on the barrel are not always concentric to the bore.  This doesn't matter with a regular flash hider or compensator but with the suppressor being off just a few thousands of a inch can create baffel strikes.

Some supressor use a "quick detach" method over the existing flash hider or compensator.  The same problems can arise if this is not perfectly concentric to the bore.

You are about to spend $200 on the tax stamp....$600-1200 on the supressor, so don't cheap out on a $65 threading job to ensure accurate, quality threading on your barrel.





How can I make my gun "Hollywood quiet"?
Short answer: You can't.  First, the very fact that most firearms cycling of the action results in a very "loud" metallic click negate this possibility.  You also have to factor in that most rounds are "super sonic" which means that they will create a small 'sonic boom' as they come out of the barrel (just ask anyone whose worked 'the pits' at a long range match---you can hear a very loud 'crack' above your head followed by the sound of the gunshot).  Now, it is possible to use "sub sonic" ammunition in some firearm calibers while others are far too "heavy" and reducing the load would cause serious functioning problems.

What is first round pop?
FRP is related to a louder-than-normal report. This occurs when oxygen is present within a suppressor. Since 1/5th of our atmosphere is oxygen, FRP usually occurs when the very first shot is taken. Few (if any) gun powders retain enough chemical oxygen internally to allow total and complete combustion in the cartridge case and barrel. These hot combustion gasses often reignite after they reenter the primary chamber in a silencer on the first shot. Subsequent shots delivered in close succession are usually much quieter than the first shot in a sequence. FRP will reoccur when another shot is taken a few minutes later, as more oxygen will gradually reenter a silencer that is not sealed off from the atmosphere. FRP can be minimized with careful design, and with a very small primary expansion chamber, but it is considered a major problem within the suppressor industry. FRP can be a problem with compact cans, extremely short pistol barrels and center fire cans. A small primary expansion chamber in .223, .308, .50 BMG and heavier calibers will soon damage a rifle’s muzzle due to a plasma effect – causing accuracy to deteriorate because of premature melting and erosion of the barrel metal in the weapon’s bore.


What does it mean when someone says shooting a 'wet' can?
It means that someone has put either water, grease, or oil inside the suppressor.  Remember the part about escaping hot gases?  Well, the water does two things.  First it acts like a 'coolant'.  Cooling the gases faster means less combustion.  Second, it acts to reduce the 'volume' of the gas (this is a super scientific area that is not even worth explaining as I don't even fully understand it myself....but basically gases always maintain their 'mass' but their 'volume' can change.  If you're that interested go look up  Benoît Paul Émile Clapeyron's "Ideal gas law").

So, how long does this last?  Well, that is relative.  The effects of the water begin to degrade right after the first shot.  Some tests have shown it to last up to 30 rounds.  I've personally fired a 'wet can' on an 11.5" AR barrel and noticed the 'extra suppression' starts to degrade after 5 shots.  

It's important to know that you don't "fill the can up" with water.  Usually just dunking the can then shaking it out or adding a few table spoons of water and shaking it out will be effective.  Water tends to be more effective than both grease and oil.  Grease is not as messy as the oil but it still stays in the barrel.  

The one major drawback of a wet can is that the lead vapors can cool faster and condense inside the baffles.  A dirtier can may result in more serious problems if the suppressor gets super heated and the lead flakes off creating small "projectiles" inside the can.

ADDED BY TONY_K:
The gases that propel the bullet contain kinetic energy, and that energy has to go somewhere (see: the first law of thermodynamics, the conservation of energy, yada yada yada).

When a dry suppressor vents those gases through the baffles, the energy is converted through friction to heat (thermal energy) -- which is why suppressors get so hot.

By wetting the inside of the suppressor, the energy in the gas is instead put to work converting the artificial medium (water, oil, grease, etc.) from a liquid form to a vapor. This conversion process very efficiently uses up a tremendous amount of that energy, so there is less residual energy to generate heat -- and, more importantly, there is less residual sound.

When all of the liquid artificial medium has been converted to vapor, there is nothing left for the gases to work on, and the can gets louder again.

In theory, with sufficient volume and artificial medium for the energy to "work on," a wet suppressor would be completely silent. In reality, a centerfire round would require a suppressor the size of a 55-gallon drum to do so.

Also note that air and gases can be compressed, while water (and artificial media) cannot. Suppressors are designed and built to withstand a certain level of pressure before the seams let go and they grenade. The pressure generated by venting a given caliber's gases into a can of known volume can be calculated, and the suppressor is built to withstand that level.

But adding non-compressible media reduces the volume remaining to contain the expanding gases. Putting the same amount of gas into a smaller volume raises pressure levels -- and, in some cases, beyond the suppressor's design strength.

The lesson herein: Unless your suppressor is rated for wet use, contact the manufacturer before adding any artificial medium.

What's a "Gas Buster" and why do I need it?
A great deal of gas/lubricant/lead vapor is blown back through the upper receiver out the back near the charging handle area on an AR15/AR10.  This is magnified when using a suppressor.  One way to combat this is by using a "gas buster" handle.  This proprietary charging handle uses a higher "shelf" on the rear of the handle area which blocks the gases from coming out the top into the shooters eye.

A "poor mans gas buster" can be made by using a little RTV (room temperature vulcanizing) sealant in the gap between the upper receiver and charging handle.

Much of this should be somewhat of a non issue however if you are always shooting with eye protection.  Safety glasses are more than just an 'annoying range rule'.  Regardless of what type of firearms activity you are engaged in....eye and ear protection should always be utilized (life or death CCW confrontations aside).

Can I use a .223 suppressor on my 22LR ?
Yes, but this is not recommended by some knowledgeable people in the industry.  The main reason is that 22LR causes a great deal of fouling in the internals of the can which requires a great deal of cleaning and can necessitate a can that is able to be taken apart by the end user.  If the can cannot be taken apart then it is much more difficult to clean.  But more importantly is what will happen when you switch over to .223.  First, a solid can that is welded is more durable and better suited for heavy use of a .223 caliber weapon.  The problem is going to arise however when the .223 heats up the can to much higher temps than the .22LR did.  In the process this could knock some of the fouling build up that remains in the can from the 22LR which in turn could cause serious damage to the baffles as it’s blown out the barrel.  This is almost like a plasma cutter effect.  The baffles could already be superheated from extended or full auto fire making the internals "soft".  The hot carbon that got knocked loose could now be blown out the can striking the baffles on the way out and chewing them up little by little.  Over time by switching back and forth between heavy use this could really eat up the internals.


Baffle strikes, what are they and what causes them ?
As the round leaves the barrel is passes through a series of "chambers" called baffles.  When a round is not properly stabilized it can "wobble" off center and can touch the interior of the suppressor.  This can be caused by an improper twist rate (too slow or bullet too heavy), an overheated barrel and suppressor, or by rounds that do not have enough powder for the correct velocity.  The last issue can depend on bullet caliber.  While generally most manufactures will rate their .22LR and .223 cans to be used with subsonic ammo many state that subsonic .308 is not recommended.  This is due to the fact that pushing that large .308 round down the barrel at subsonic speeds is not enough to suitably stabilize the bullet which can lead to a baffle strike.

Another issue which can cause a baffle strike is an improperly mounted suppressor.  Before mounting you must first ensure that the threads on the barrel are properly lined up with the bore axis.  Although someone may be good enough to use a "die" to cut the threads by hand the only "sure way" is to have a competent machinist/gunsmith cut the threads on a lathe.  Next, if it is thread-on mounted then proper procedures must be followed to ensure a tight/correct fit. (Don't ask me what these are as I am nowhere near informed enough to comment on this---someone who is please feel free to add that section).  If it is QD mounted then the adapter must be correctly mounted in a similar fashion to ensure it is lined up with the bore axis.


How about traveling with a suppressor across states lines?

ADDED BY TONY_K
Approved 5320.20s are required for interstate transportation of all NFA items except suppressors and AOWs.

If you are transporting other types of NFA, it's worth getting .20s for your suppressors and AOWs as well as a CYA. Many LE do not know AOWs and cans are exempt from .20s, and will wonder why they aren't on your approved list.

BATFE will approve a 5320.20 for suppressors and AOWs if you submit one.

As far as notifying out-of-state authorities ... no notice is required to travel through a state -- that is protected under FOPA '86. Some states do have their own requirements for visitors, though, so if you want to shoot NFA at your destination, check in the hometown forums about that state's regs. (IIRC, Va., N.C. and Mass. regulate visitors' NFA, but don't hold me to that.)



Can I make a silencer out of a soda bottle or potato?
If it weren't for the fact that people believe a lot of the stuff they see on TV it would be laughable at some of the things we see.  The answer to the above is not so straight forward.  First, you can do what ever you want as long as you are willing to risk going to prison and possibly ruining your firearm at the same time.

What level of suppression you get out of a soda bottle is also relative.  Even if it only lowered the sound level by 1 decibel the BATFE would consider it a suppressor/silencer by NFA standards and would be regulated (which is why having a real XM177 moderator is foolish because they only lowered the dB by about 2-3 decibels at best---not worth the NFA headache).

So if you are willing to skirt the law, and have a suppressor that will only lower the sound by a marginal amount then yes you could theoretically.  You can also put your hand on a hot stove if you wanted to....let us know how that turns out for you.


OK, who else wants  to add some stuff?

Please post and correct where I am wrong or if additional info is needed.

you can use a lawyer or a will maker program here is a link for writing a trust using quickens will maker click this.  i myself used a lawyer to write a trust for me.

I'm new to a lot of this. As far as I can tell the only reason to set up a trust is to speed up the process of getting your BATF tax stamps. Is there more to it than that?

You can add/remove people to the trust. Works great for family members that want access to the NFA item, if you don't have a will done right now, it helps there too.





 

Ok so im new to the whole suppressor thing and this may already be covered. Can a suppressor wear out? Im assuming sense a barrel can a suppressor can also... and if they can how fast?

The blast baffle can errode over time, but its more a function of what the host firearm is and what caliber.  We are still talking thousands and thousands of rounds.  Something like a 22lr isnt going to wear out if you keep it clean.

Which suppressor manufacturers can I use on HK USP stock threaded barrels for 9mm, 40 and 45ACP?

And which one is the quietest?

Lots of great info in this thread.  I'm looking to pickup a suppressor this year or next and had no idea about the steps involved or setting up a trust.

I have no problem doing the steps involved to complete the form1.. but should I still do the trust anyways?  Seems like its just an easier way to go.  

Also Im planning on SBR'ing a lower this year.. Im guessing the same rules apply (form1, trust, etc..)??

Can I use a .30 caliber suppressor on my 5.56 rifle?
Yes. For the bazillionth time. YES.

Please find a more tactful way to add this to the OP.

Can I use a .308 can on a .223 rifle?

Just kidding.

What's the average wait time right now for form 4 suppressors? I just submitted mine last week. Is there any chance of having it in hand before june?

3-5 months is average right now on a form 4.

I sent mine off on 12/29/10 and it got approved on 3/18/11. Got a call from the dealer yesterday to pick it up.

On a side note do I need to keep just the copy of the form with the stamp, copy of the trust or both?

EDIT: Found what I was looking for- thanks.

Can one legally obtain a supressor if they have multiple residences? One in CA and one in AZ. Of course the suppresor would stay in AZ. Thanks..
Should I just contact BATF? Thanks!

A person can own a title 2 firearm at any address they actually live at.  Look here.  http://edocket.access.gpo.gov/cfr_2001/aprqtr/27cfr178.11.htm



Ranb

Suppressors are legal in KS, and are also legal hunting equipment as of 7/2011

Why are some suppressors made able to be disassemble while others are not?
Is one better then the other?
I would think that it would be better to be able to disassemble a suppressor for cleaning after using corrosive ammo, is this right?

Michigan now allows silencers if the starter of this thread wants to update.


Some silencers can be disassembled for cleaning, all .22 rimfire for cleaning.


Some mfg's center fire are sealed, they say its because its a much faster jacketed round and the gasses are hotter


so it stays clean, I personally think they don't want you to see their design and baffle stack.


I think they need to be disassembled and cleaned like any other gun you own.

 

Missouri now allows individual ownership of Surpressors as of August 28th 2011.

Any NFA item now requires no C&R.  

HELP !!!!  I'm also new to the site and THE WORLD OF SILENCERS, what is the difference of going to your leo and doing as a llc. PLZ HELP ME OUT.  

.22 LR is wax lubricated.  This causes buildup of wax and dirt.  Eventually, it will clog, rendering it useless. You can afford to do this.  Centerfire cartridges don't have wax lube.  It would take many more rounds to clog a centerfire.



Design and baffle stack?  X-ray?  Fill it full of water and ultrasound imaging?  It is cheaper to make an all-welded than machine threads.



 

The difference?  Your local chief LEO is probably a politician.  And is worried about news articles showing him to approve these items.  So they won't.  



Check your HTF to see if this is the case.  4-5 months for Atlanta to cash a check is long enough, don't wait on your local chief.  A trust also eliminates fingerprinting so you are not on the radar.  You still will get NICS from the dealer and from BATFE.



 

I read all the posts and if I missed this question I apologize.

I will be traveling through a non suppressor state, California, is it legal to transport one though the state just so long as it is not used or taken out of a locked box?    Or can I ship it to myself at the other end of the trip?

i would ship it or avoid CA.  No reason to risk it with those commie bastards.

Yea I would like to avoid Ca.  Unfortunately,  I would be picking up my son in San Diego.  Not picking up the son just having to drive through Ca.  I would also be taking my ar10's.  I would have to disassemble them but no biggie.

Well. I just read part of the 2006 ca gun laws booklet.  I cannot possess or transport any suppressor through the state.  I cannot possess any magazines that holds more than 10 rounds. Nor can I possess any firearm that has a detachable magazine that is capable of holding more than 10 rounds. My ar10's are assault weapons because they have a detachable magazine and a pistol grip and flash suppressors so not legal even in broken down pieces.  Not only that but I cannot even possess a "sniperscope", read night vision scope, in california.   I guess that blows my plans for my next pig  hunt unless I ship just about everything.  Wow that really sucks.

that would presuppose the baffle openings are the same size as the bullet. They are necesarilly larger than the bullet. How much so depends on the manufacturer. While it is POSSIBLE you could have clearance to fit the .355 9mm bullet, it's doubtful you would. you better ask your manufacturer first.

Michigan doe's allow civilian ownership of C3. RECENTLY PASSED.

What is C3? Are you talking about suppressors?





 

How does a can work with a piston system?  Is the gas divereted more/less?  Is there more/less blowback from the CH?

OK, this may be a stupid newbie question, but is there a specific legal definition for what is and/or isn't a silencer?
(I mean for example, does it have to be attached to the end of the barrel or the gun at all?, that sort of thing, or is it anything that makes a loud boom lees loud?)

can anyone that mmets rquirements get one, or do you have to for a LLC of some sort or a buisness? TIA

Researching and can't find a source cited answer for this. Can a Form 1 fabricator perform repair work on the can they build? Example would be replacing a damaged end cap.

No.  It sucks and is stupid, but no.

How about a FAQ section on cleaning tips for both types of cans? Sealed and those that can be disassembled...

+1

I know a 9mm can's use a 30cal can, but can a 30cal (300BLKOUT) use a 9mm can?

You're gonna have a bad time if you try to put a 9mm (.355) through a .30cal can.

Some 9mm cans are rated to handle subsonic .300blk.  Check with your specific can manufacturer to see if yours is.

Stupid computer, I meant to say I know a 9mm host CAN'T use a 30cal can, but was wondering if anyone tried a 9mm can on a 300BO host.

As said, a 9mm suppressor can sometimes handle subsonic 300 blackout. Depends on the can, and ONLY is good for subsonic.

DOJ is proposing rule changes to the NFA trust that would require that "responsible persons" of the trust have the same BI, Fingerprints, and CLEO sign off that are required for individuals.  For those that use the trust to circumvent CLEOs that refuse to sign off on the purchase this will effectively prevent them from owning class 3 items.  Here is a link to an NFA gun trust lawyer with a link to the actual DOD document.  These rule changes could become effective as early as June of this year.

.myguntrust.com/are-nfa-gun-trusts-being-eliminated.html  (add the www)

Full disclosure, Jim Willi set up my trust.

ETA:  This wasnt intended as an ad but if anyone feels it is out of line I will delete the link (dont have another link to the document)

+2

+3
In the meantime here are my .02...
I use a 50/50 mix of Hydrogen Peroxide and White Vinegar.
Drop it in there for at least 3 hours....ONLY WATCH OUT FOR ALUMINUM PARTS. clean those by hand!

Hey guys. So a good suppressor is on my short list. I want to purchase a Surefire Socom556-RC. I've read some archived threads and it seems like people have been able to purchase the can for less than the $1375 price advertised. I don't have a dealer near me so are there any online dealers where it might be cheaper?

Yep. Just found it for $1157 w/ free shipping at the first place I looked. Just check the most popular and highly recommended silencer shop online.

Ok awesome. Thank you!

And then I found it $10 cheaper here, but they charge $8.95 shipping...so you'd still save > $1!!

I just got off the phone with someone at the silencer shop and they told me the Saker made by Silencer Co. is better than the Sure Fire. He said it's just as accurate, reduces the noise more, is easier to put on, and is $850 with a mount! Is the Saker really better??? Because that's great deal.