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.

So is there a mandatory waiting time when you buy a suppressor?

Yes. It's an approval process...which means waiting time for you. And yes, you pay the cost of the suppressor and the $200 tax stamp up front (plus any applicable taxes and transfer fees) and then wait. You are allowed to go "visit" your can and shoot with it if your dealer has a range.

And an additional wait time if you choose to buy from out-of-state and need it transferred to a local dealer first.

To give you an idea...I bought two last year, both in the late Aug/early Sep timeframe, and haven't seen them, yet. Expecting them in the next week or two based on current trends.

Sounds like a nightmare!

Kansas allows Suppresors, Machine Guns, SBR's and AOW's for personal ownership.

We also have the "Made in Kansas" bill which allows a resident of Kansas to build a suppressor without using a Form 1 to the ATF. As long as it is for personal use and not for sale. I would not risk that with the ATF and would buy some $200 insurance (Form 1 with $200 Check) to cover my ass. Federal Laws trump State laws so it is better to be safe than sorry.

Well I'm in Oklahoma. I don't know what our laws are, but if it's going to be that much of a hassle I might just put the money towards a new revolver.

I am new to suppressors and this forum, so I would imagine this question has come up before. I submitted my tax stamp app in April and hopefully will get it soon. My first build will be fairly basic for .243 Win, using 34.3 mm freeze plugs as baffles. QUESTION: Is there a standard or optimum over-drill/clearance for the baffle passage? The clearance or gap between the bullet and the passage or tunnel it travels through? I have been advised that a good standard would be .026 mm gap or over-drill from the actual bullet size = a .269 passage for the .243. I have found two bits that are very close: a letter "I" bit at .2720 giving .029 clearance - or - a "H" bit at .2660 giving .023 clearance.

If this project works well, I plan a later, longer over-barrel .308 suppressor using a 8,5 metric bit at .3346, giving .0266 clearance.

Am also now getting some feedback that this tolerance is way to close --- suggestions that .060 clearance/gap is more to standard????

This is of course a pretty critical part of the build, soooo --- Am I stumbling down the right path here ??

If you mailed off your form 1 in April, as an individual, you have a solid 4+ months more to get your stamp.
If you filed on a trust using the eForms, maybe a month more. Waiting times are starting to speed up, but still...

For building from scratch, you can find a lot of information here and over at silencertalk.

.060 is pretty standard. People typically use a 3/8" bit for .30 cal freeze plugs because 3/8" bits are so common

I found this info really useful regarding engraving.

If you are holding an Application for Tax Paid Transfer and Registration of Firearm (labeled on the top right of the form), or ATF Form 4 (labeled on the bottom right of the form), then you are not a manufacturer, importer (into the U.S.), or maker of the firearm, thus there is no engraving requirement.  If you are holding an Application to Make and Register a Firearm (labeled on the top right of the form), or ATF Form 1 (labeled on the bottom right of the form), then you are either a manufacturer or maker of a firearm, thus there is an engraving requirement.

That's about as basic a bit of info as anybody getting into the NFA world should know. If they don't, they've done themselves a disservice by having done insufficient research before submitting a form.

An F1 is to make (build)...so you're a maker, nothing else. Importing and manufacturing is a whole different ballgame as far as forms, taxes, statutes, etc.
An F4 is to transfer (buy)...so somebody else has already made, manufacturered and/or imported the firearm.

You can even F4 an item made via an F1, and the new owner has no additional engraving requirements.

New to the suppressor thing here too.  I have a Saker 762 that i am going to put on my Rock River AR.  Do i, should i get an adjustable gas block for it?  Will it shoot fine with out it?   Thanks for any help

Not sure if already mentioned, but MI now allows supessors and SBRs/SBSs.  I noticed in the OP it stated we did not, this changed recently.

decibels by distance from an older thread.  An example of noise pollution for the shooter and neighbors.

http://hyperphysics.phy-astr.gsu.edu/hbase/acoustic/isprob2.html


Gunshot  167 dB @ 1m  = 127 dB @ 100m and @ 1000m is 107dB

Gunshot  135 dB @ 1m   = 95 dB @ 100m and @ 1000m is 75 dB (example of a suppressed rifle)

Minnesota legalized suppressors effective July 1 2015.

Vermont finally legalized suppressors as of July 2nd! http://americansuppressorassociation.com/vermont-becomes-41st-state-to-legalize-suppressors-effective-july-2/

Might be helpful for the informational purposes of this thread to know which of the states not listed in a much earlier post



have exemptions for law enforcement officers

While its not a popular thing to admit on this site because some people make snarky comments about "some animals blah blah whatever", some states do exempt individual officers from purchase restrictions that apply to non-LEO

edit: based on reading some of the follow up posts, that original list of states needs to be updated

edit:

Since my post generated no replies, I'll start.
NYS Penal law 265,02 is what criminalizes suppressor ownership in NYS

S 265.02 Criminal possession of a weapon in the third degree.
 A person is guilty of criminal possession of a weapon in the third degree when:

   (2) Such person possesses any explosive or incendiary bomb, bombshell,
 firearm silencer.....,

PL 265.20 lists exemptions to the above
S 265.20 Exemptions.
  a.  Paragraph  (h)  of  subdivision  twenty-two  of section 265.00 and
 sections 265.01, 265.01-a, subdivision one of section 265.01-b,  265.02,
 265.03,  265.04, 265.05, 265.10, 265.11, 265.12, 265.13, 265.15, 265.36,
 265.37 and 270.05 shall not apply to:
   1. Possession of  any  of  the  weapons,  instruments,  appliances  or
 substances  specified in sections 265.01, 265.02, 265.03, 265.04, 265.05
 and 270.05 by the following:
   (a) Persons in the military service of the state of New York when duly
 authorized by regulations issued by the adjutant general to possess  the
 same.
   (b)  Police  officers as defined in subdivision thirty-four of section
 1.20 of the criminal procedure law.

additional exemptions to the suppressor and other NYS firearms laws at the link
http://ypdcrime.com/penal.law/article265.htm#p265.04

My buddy had a DUI approx. 2.5yrs ago. No issues passing a 4473 or NFA purchases.

I don't know if OP is still being updated or not, but Kansas does allow private ownership of suppressors.

That's it, thanks!



 

Nvm

Iowa is now Suppressor friendly. Whoowhoo

You can change the first page now

If my suppressor requires a form 3, can the local dealer send off a form 4 before they have physical possession of the silencer?

I would like someone to talk more about how the supressor actually attaches to the barrel. The FAQ made it sound like additional threading had to be done by a local machinist. A person cannot just buy a threaded barrel? How do QD attachments work?

Use this an an example. A person buys a stock handgun (Glock 17, H&K USP .40, take your pick), and a can. What must happen next to connect the two? Please show pics if possible.

Unless it's a suppressor ready model, you have to buy a threaded barrel. 87% of the time, it's plug and play switching. My 1911 barrel was semi fit
Check lone wolf, silencerco, barsto, storm lake, and KKM.
For one off scenarios, a gunsmith can make a custom extension for your barrel or in the base of a like a beretta 92, just thread the extended portion

This is my beretta

I have a question.

User serviceable.

Why would you buy one that isn't? No good options?

I am waiting for my first can, so I am not trying to be a know-it-all, but at this point in history shouldn't they all be user serviceable? It should also be listed at the top of the info right under the caliber.

Right?

Ah ok thank you.

What’s the life expectancy of a stainless vs Iconel baffle stack in a rifle, assuming 16”+? I understand sbrs are rough on cans but wondering if Stellite is always the way to go for centerfire rifle.

A lot of the time, Stellite and Inconel are used for the blast baffle, the first baffle in the stack. That baffle takes the brunt of the damage, so the stronger the better. Past that, a lot of companies use stainless and it holds up fine. If you plan on using it mostly on 16"+ guns, I wouldn't worry about stainless baffles with an inconel or stellite blast baffle at all.

Buy threaded barrel.  Install barrel. Screw pistol to can.  Shoot.

Attached File


Threaded barrel

No Neilson device?

4 pages of reading and this one hasn't been addressed, nor is it covered on ATF.gov.

I live in a suppressor legal state, TX, but am considering a move to another state, CO or MT, also suppressor legal. What happens if I end up moving before approval of the Form 4?

1. Pick up suppressor once approved, assuming you’re technically that states resident still at that time. I believe most states give you 6months to change over residencies.

2. You’re a resident of the new state officially. Form 4 gets cancelled, get you’re $200 back and start the process over in the new state.

Depends.  Depends on the rate of fire, how hot you get the can, the design of the blast baffle, the ammo, lots of things.

I've got carbon steel cans that have lasted thousands of rounds just fine because they only get used on a bolt gun and the blast baffle was specifically designed not to wear or peen.

While I'm waiting in limbo,  can I have my suppressor transferred from one dealer to the next?  My shop just acquired their SOT and it's closer than the one I'm currently using for transfer.

Ok.  Thank you for the information.  At this point I’m not sure what to do.  I guess keep waiting.

Keep waiting is all you need to know.

A couple questions...

Existing sealed aluminum 22LR can - what is the best cleaning method? Radiant556 idea sounds great, but it doesn’t seem like he likes it for aluminum.

New .30 cal can. Will be primarily used on 5.56 10.5-16” BBLs. If the can is threaded 5/8, and I use a break/flash hider as a mount - is the 5/8 thread on the muzzle device? Are the muzzle devices proprietary to the cans?

Also, what material would you recommend for the new can? I’m a little concerned about aluminum with the muzzle pressure and potentially stripping threads. I’d love to keep the weight down though.

If the can is listed as 5/8x24, that means it has a direct thread mount and you have to remove any existing brake/FH and screw the can directly onto the threaded muzzle.  If you want to use a brake/FH as a mount, you have to replace the direct thread adapter with the adapter for the mount.  There is some cross compatibility with mounts between companies, but some are still proprietary.

I don’t think you’ll find a can rated for 10.5” 5.56 made out of aluminum.  As a minimum, the tube and baffles are going to be stainless steel.  Some may have titanium baffles to keep the weight down.

Yes. But you should be asking what is the best can for your needs and hosts.

New to the forum and almost a suppressor owner but need some guidance.  I was living in Alaska and purchased a suppressor and sent in my form 4 through my local NFA dealer.  While I was waiting for the form to be approved life happens and I had to move for my job to another NFA friendly state.  But, before I moved my form was approved and I hoped it would arrive prior to me having to leave the state.  So now my approved stamp and suppressor are in AK and I am in Colorado.  So what is the easiest wind quickest way for me to get the can?  Can my AK dealer ship it to a local dealer in CO and he transfer it to me?  I’m hoping I don’t have to start the process all over after having to wait so long once already.  Appreciate any ideas.

I've been thinking about dipping my toes in the pool. I read through and didn't see anything on this. Is it correct that there aren't any yearly hassles such as renewals, phone calls, etc. associated with owning suppressors (or SBR's)? It's just a one and done thing... and make sure you keep your paperwork handy?

Thanks.