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Old October 15, 2010, 03:01 PM   #1
hal9000
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Legal and technical requirements for DIY silencer?

Since this is my first post I guess I should lay a little groundwork.

I'm a former NRA rifle instructor, I have a family member who is also a former NRA instructor and FFL holder and owns a (legally) suppressed firearm. Neither one of us is an expert on NFA regulations however. I'm also a former jeweler and metal smith and enjoy doing things myself whenever possible. "I made that" is a lifelong mantra for me. For items that are beyond my skill level, I have access to a machine shop and a qualified machinist who can help.

On to business: I'm building up a ruger 10-22. I've wanted one for years and finally found a deal I couldn't pass up. On my list of maybe's is adding a suppressor (the barrel I installed is threaded). If I do suppress it I'd really like to take a stab at building one myself. Which leads to several questions.

1) How do I go about legally building and registering a suppressor? IE, do I need to contact ATF first and get permission before I start, or take the finished item to them? (I imagine is has to be the first). Is there a separate ATF process for building your own suppressor vs. purchasing one? What forms (I'm sure there are several) do I need to file?

2) are there any good resources in terms of DIY suppressor design and construction? OR does anybody sell components for hobby builders?

3) if I need assistance, say from a more skilled machinist, do they need any kind of special permission or licensing to perform the work? I don't want to get anybody else in trouble.

If I follow through, this will be my first foray into the realm of suppressed firearms. Any advice you can give to keep me on the right path (both legally and in terms of getting good results) is welcome.

To shortcut the inevitable "use the search button" response. I looked around a bit here and elsewhere to no avail, probably because I'm not that familiar with the right terminology.

Thanks in advance for the help.
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Old October 15, 2010, 03:46 PM   #2
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Basically you fill out the ATF form 1 in duplicate, get your local sheriff to sign the back, attach passport sized photos (photocopies will do) and send it in to the address on the top of the form along with two fingerprint cards, form 5330.20 and a check for $200. The check will be cashed in a week or two, approval takes 4-6 months and improving since the "Obama was elected panic" situation which caused a huge upsurge in the number of applications. ATF forms are available for download from the ATF webpage, or you can order them for free there also.

The best website for design is Silencer Talk. I and other members have posted many drawings there. The 10/22 is nearly ideal for suppression, even with a 1x6 inch can with flat washers for baffles. It sounds very nice with subsonic ammo.

The most important thing (after obtaining the approved ATF form 1) is to have threads cut onto the muzzle that are very straight to allow for proper alignment. A hand held die will not do this. A gunsmith can do it for a reasonable price, just tell him/her it is for mounting a silencer so they understand the threads have to be good.

I order tubing and bar stock from Online Metals in Seattle.

While a person needs a license or an approved ATF form 1 to make any silencer parts, you can outsource the labor to anyone without a license as long as you are present while the parts are being made and take them home with you at the end of the day. It is easy to make a silencer though. I learned how to operate a metal lathe for the first time when making my first silence for a 300 whisper.

AZ is one of the 37 states that allow unlicensed civilians to own silencers. Let me know if you want drawings. There are some posted one this forum, but SilencerTalk.com is still the best place.

Ranb
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Old October 15, 2010, 03:57 PM   #3
hal9000
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Thanks for all the information RAnb. I didn't expect such a good response so soon.

I have to finish assembling the rifle before I really start to worry about the whether I'll actually build a suppressor (that's this weekend's project). But drawings would be great. Honestly, I wouldn't have given any thought to suppressing this rifle if it wasn't for the threaded barrel. Now I keep looking at it and tellilng myself its a shame to let those threads go to waste.

I'll go check silencertalk.com and see what they have, but it sounds like you might have something particular in mind. Is there a generally accepted "favorite" or "best" design? I've heard how easy it is to suppress a .22 but I'm thinking that durability and cleanability may come into play in the long run.
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Old October 15, 2010, 04:01 PM   #4
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Here is a pic of a 22lr silencer. My final product rarely looks exactly like the drawing. I used a short simple 60 degree cone for the blast (first) baffle. It is a good idea to use steel for the blast baffle and reat end cap that screws onto the barrel for wear resistance. Aluminum is fine for all the other parts of a 22lr can unless you plan on using it on a machinegun, then it should be all steel.



A simple 60 degree conical baffle.


The M baffle is just a conical baffle with the spacer attached. I think they are harder to machine so I make mine with the spacer separate.

A step cone baffle. Should make more turbulence (a good thing) in the silencer.


Conical baffles are usually separated by spacers which are usually just thin pieces of tubing machined to just under the Silencer ID.

A K baffle, as it resembles the letter K. Usually used without spacers and will stay aligned to the bore even if it is not held in tight. It is not as strong as a conicl baffle of the same weight as the front flange can collapse under great stress. I only had this happen when hammering stuck baffles out of a dirty can for cleaning. The 0.050" thick 4130 K baffles I use in my 338 ultra mag are holding up fine.



Some parts of my last 22lr silencer. Shows the rear end cap with blast chamber spacer built in, a conical baffle, a step cone baffle, cone baffle, front end cap and a spanner wrench.



Ranb

Last edited by RAnb; October 15, 2010 at 04:45 PM.
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Old October 15, 2010, 04:04 PM   #5
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Quote:
Thanks for all the information RAnb. I didn't expect such a good response so soon.
Welcome. All I ask in return is that anytime someone tries to tell you that silencers are illegal in the USA, you jump down their throat and rip out their lungs for me. Then ask them what law bans them. I have been fighting to get the law banning silencer use in WA amended and those jerks trying to tell me that silencers are illegal are the second biggest obstacle. Apathetic gun owners are the first.

Ranb

ETA; I am at work, the is nothing to do, the boss will not let me go home and the shipyard recently allowed access to various websites through the firewall.

Last edited by RAnb; October 15, 2010 at 04:46 PM.
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Old October 15, 2010, 04:37 PM   #6
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Quote:
Is there a generally accepted "favorite" or "best" design? I've heard how easy it is to suppress a .22 but I'm thinking that durability and cleanability may come into play in the long run.
There is no best design. Weight, size, cost, effectiveness and durability are all factors and one has to compromise. The lightest weight silencer will not be come apart and will not last long during rapid fire. A can made from titanium will be expensive. Non-stainless will rust, especially if you use it with water to further suppress the noise. Threading requires thicker and heavier tubing walls than a sealed (welded, glued) can.

The 22lr is very dirty, it leaves lots of gun powder crud and lead behind as most of the ammo is not jacketed, it is either waxed or plated which is the same as bare lead by the time it leaves the barrel. You can clean a sealed can, but is is harder and less effective as cleaning is limited to solvents and rinsing. Some manufacturers will also take cans in for cleaning, but I am not sure if they will do it for a homemade form 1 can.

My fist 22lr can was made from 1 inch aluminum tubing with .070” (?) walls and 7/8-24 threaded end caps. It worked ok, but was a bit louder than a sealed AAC silencer. My second 22lr can was made from 4130 tubing which allowed me to use smaller 15/16-32 threads. The thinner walls meant more volume. I also used thinner baffles and spacers to maximize the volume.

The only bad thing about form 1 cans is that you have to make them right the first time. You cannot replace parts except for wipes. Repairs are limited to those that do not involve changing bore size or making the silencer longer. You can send it to a class 2 for parts replacement, but they cannot change the bore or make it longer either. Wipes are the only parts that you can replace without paying another $200 tax. Wipes are rubber disks the bullet punch through. They are very effective at reducing noise until they wear out in a few dozen rounds. Since they touch the bullet, accuracy is also degraded.

Ranb

Last edited by RAnb; October 15, 2010 at 04:44 PM.
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Old October 15, 2010, 05:11 PM   #7
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If you decide to fabricate a can, do you have to send drawings of your design for the can? Do you need to provide all the threading dimentions and such as well?

I find this topic quite interesting.

Are there any books you would recommend on suppressor design and theory?
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Old October 15, 2010, 06:33 PM   #8
hal9000
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Thanks again Ranb.

I'm sure I can't be the only person to suggest using an ultrasonic cleaner to clean one piece silencers. Seems like that would be very effective, and they're cheap enough these days (even Harbor freight has them, but you can get used ones from vet clinics and jewelery stores on occasion).

I can already tell I'm going to be nerding out on silencers this weekend...
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Old October 15, 2010, 07:02 PM   #9
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Never supply more than is absolutely required on the ATF form 1. You are not required to supply an overall length, plans or a drawing. It limits you too much. My finished product rarely looks like what I drew up when I submitted the ATF form 1. I am always changing my mind about things.

I have heard of some people getting their ATF form 1 sent back because they did not fill in an overall length. You can minimize this by not leaving anything blank. Fill in N/A for the overall length.

A form 1 silencer is never a prototype, so plans are not required.

I have never seen any book that had good silencer plans. The ones that sell on Amazon that have plans for silencers that require only hand tools suck in my opinion. They typically are too long and too wide, block the sights and will potentially cause baffles strikes which ruin accuracy at best or destroy the silencer at worst.

Al Paulson's books Silencer History and Performance are very good reference material, but they do not contain modern silencer plans or drawings.

A good silencer has near perfect alignment to the bore. This requires a lathe to thread the barrel and make the end caps and baffles. It is very easy to do on a lathe with little or no training, but very difficult to do with hand tools. I only saw one good example of a decent silencer made with hand tools on SilencerTalk.com and I will not try to replicate his project.

The drawings and photos I put up work very well. They are not as good as what the pros can do, but you may need a proper noise meter (with <20micro second rise time >$3500) to tell the difference. What I am not able to do (yet) is make good monocores, welded baffle stacks (stronger for the weight) and excellent finishes. Some conical baffles are precisely machined in an asymmetrical pattern to make the gases more turbulent. These are proprietary designs that can only be revealed by buying one and cutting it apart. Silencer design has progressed a lot in the last thirty years and people are not always willing to share their ideas.

I share mine as part of my dream to promote silencer use and change the WA law banning their use. I am years behind the professionals anyway. But I am having fun.

Ranb

Last edited by RAnb; October 15, 2010 at 07:30 PM.
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Old October 15, 2010, 07:04 PM   #10
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I heard the ultrasonic cleaners work ok, but can pit aluminum. I do not know as all of my aluminum cans come apart for cleaning.

Ranb
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Old October 15, 2010, 07:26 PM   #11
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Quote:
I can already tell I'm going to be nerding out on silencers this weekend...
Funny you should say that. As much as I get to hear how gun nut, lunatic fringe, criminal and other stereotypes I am, I come off as rather nerdy in person. I show up at the rifle range with my shorts, t-shirt and flip flops on touting a suppressed AR-15 or a 338 ultra-mag sniper rifle with a 30 inch barrel and foot long silencer on it.

I am as difficult to pigeon hole as any other independent, pro-choise, non-homophobic, atheist, gun nut out there hahahahha. Hell, I even believe that dog Obama was born in the USA and Reagen and Bush Jr were bad for gun owners. This has made me rather unpopular in some places.

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Old October 16, 2010, 12:59 PM   #12
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Something I forgot to add, simple instructions on how to make a baffle. For a step cone, just machine the exterior of the baffle first, then cut it off from the bar stock. Then hold the baffle by the largest step in the chuck and machine the interior.



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Old October 16, 2010, 07:31 PM   #13
hal9000
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Quote:
Funny you should say that. As much as I get to hear how gun nut, lunatic fringe, criminal and other stereotypes I am, I come off as rather nerdy in person. I show up at the rifle range with my shorts, t-shirt and flip flops on touting a suppressed AR-15 or a 338 ultra-mag sniper rifle with a 30 inch barrel and foot long silencer on it.

I am as difficult to pigeon hole as any other independent, pro-choise, non-homophobic, atheist, gun nut out there hahahahha. Hell, I even believe that dog Obama was born in the USA and Reagen and Bush Jr were bad for gun owners. This has made me rather unpopular in some places.
Ranb, I have a feeling that if we lived in the same place we'd get along pretty well.

In regards to the conical baffles, I was thinking about it today as I did some other errands, and I think I could press form them from annealed aluminum sheet stock. Is there any reason that wouldn't work?

What types of finishes are you trying to achieve? I might be able to help you out with a few tips from my jeweler days. Finishing metal is usually just a matter of being detail oriented and following the right steps.
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Old October 16, 2010, 09:21 PM   #14
hal9000
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In terms of the ultrasonic damaging an aluminum suppressor, they really shouldn't. First of all, most modern ones are adjustable so you can tune the frequency they work at. Second, most are very low power. You can immerse you hand in them with no pain or damage (it will clean the grit out from under your fingernails though).

I could see an ultrasonic damaging a poorly applied finish, or if you just drop the silencer in, maybe scuffing the outside finish as it vibrates against the vessel. You should always hang items in a plastic lined basket or by a wire in the cleaner.

One other possibility might be residual cleaner or moisture causing corrosion on the inside of a suppressor after the fact. Aluminum does strange things when left in contact with water for long periods of time.

That being said, it would be worth doing some testing before hand if you ever decided to use one.

Last edited by hal9000; October 18, 2010 at 09:51 AM.
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Old October 17, 2010, 02:06 PM   #15
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I tried to make my first baffles from stainless sheet metal by forming it between two dies. But I was not able to get the deep 60 degree cone I wanted. The metal kept on tearing. There are others on SilencerTalk that have made them from sheet metal. I have not tried aluminum.

My finishes consist of bare aluminum that is sanded on the lathe or bead blasted. This finish is easy and covers up some blemishes. My first welded steel cans I ground down the bead then trimmed on the lathe to make them flush. If I had a TIG welder (or was any good at welding) I would leave the bead in place.

I painted the first few steel cans with rustoleum, it is harder than wood stove paint and I felt that bubbling paint would be a good indicator for the shooter to back off on the rate of fire a bit. My last 22lr and 223 rem cans were made with a smoother 4130 steel finish, so I blued them and think they came out rather nice; compared to the others anyway.

I clean the metal with hot soapy water then an alcohol rag before painting or bluing. It seems to work well.

Ranb
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Old October 17, 2010, 05:08 PM   #16
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I nominate this thread for Thread Of The Year in the NFA Guns and Gear section.
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Silencers have NEVER been illegal !
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Old October 18, 2010, 12:39 AM   #17
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I think electroplating would be very cool. A nickel coated silencer would be awesome, if I could get a flat matte finish. Anodizing would be nice too.

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Old October 18, 2010, 09:31 AM   #18
hal9000
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Not jewelry related really, but Anodizing is actually pretty easy to do. Here's one of the better pages on DIY anodizing I've found. If memory serves he also sells supplies.

http://www.focuser.com/atm/anodize/anodize.html

A hint on anodizing. You need to pay special attention to detail in all the prep work and pre-finishing as it doesn't cover flaws. Just provide a durable finish and maybe some additional color. (I've even seen camo anodizing jobs...)

Jewelers use small electroplating kits on a very regular basis. I never played much with nickel but other materials all worked pretty well. You can check out the rio-grande catalog online. http://www.riogrande.com/ Honestly though, I think you'd be happier with a heavier finish than the jewelers electroplating kits can provide. Commercial plating uses a lot of chemistry heavy solutions and processes. Although it can be done at home (just google home nickel plating and you'll probably get a lot of results) it's probably not worth the time or expense unless you (like me) are more interested in the process than the cost or time investment.
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Old October 18, 2010, 09:44 AM   #19
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The key to not splitting metal when you're forming it is to go slow and get a feel for when the metal reaches its limits and then stop and re-anneal it. Depending on how much you need to stretch it, you can do several steps.

Some metals are more receptive to this than others. Stainless is pretty resistant to stretching no matter what and would probably have to be formed in a different, (commercial) style die (which is a more expensive and involved process than traditional home pressure forming and I'm really not familiar with it). Aluminum, copper, brass, and maybe some of the softer steels or thin stainless could be done this way but the process would vary slightly for each metal.


I've actually come up with what I think is a simpler idea.

I had an idea for a welded cartridge type suppressor that came from a write up of a square can for an uzi over on silencertalk.com.... have you ever used a chassis punch? They're used for cutting perfectly round, burr free holes in sheet metal. The result is a circular piece of metal (with a hole perfectly centered in it) that's been stretched and deformed in two dimensions so it looks kinda like a circular pringle chip. I'm thinking that stacking those concave to concave and convex to convex, or on a 90 degree bias, pinning them through the center and tack welding at the contact points around the edge and then reaming them true might create a very nice removable cartridge. Especially if they're made of stainless. It should still be pretty light too. It would be more of a baffle style than a cone style unit (not sure if I'm using the right terminology here).

Last edited by hal9000; October 18, 2010 at 04:23 PM.
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Old October 18, 2010, 04:42 PM   #20
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Quote:
I nominate this thread for Thread Of The Year in the NFA Guns and Gear section.
+1 on that - I've been really enjoying this thread myself. Wish I had something to add - but I don't know much about silencer construction and design. Also, not quite sure how nothing more than metal pieces "silence" a gunshot? Seems to me that muffler baffle material would work better??? Do any automotive / motorcycles use similar baffling to what's in a silencer?
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Old October 18, 2010, 05:36 PM   #21
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Hal9000, thanks for the links to the anodizing and electroplating, they were enlightening. You core with the pressed baffles sounds interesting, but I am afraid the welds might fail under stress after a while if they are not against the tube wall. But I'm not sure.

My attempt at pressing sheet metal with dies was very rudimentary, I used a 6inch vise to apply pressure and I attempted to heat the metal with a propane torch. I am not surprised that I failed.

I watched a program where a guy was making aluminum pot lids by spinning a piece of aluminum sheet metal on some sort of lathe and pressing it with a round tool of some sort to mold it into a concave shape. I would like to be able to do that to make the basic shape then trim it down to the exact size required to fit snug in the tube.

I think some engine mufflers use a design that is not linear. The engineer can make the gases go any direction he wants without worrying about a projectile passing through. Anything that wears away (wipes and mesh) is a poor choise for a gun silencer unless you are able to replace it requently. The ATF allows wipe replacement, but only after destroying the ones in use.

Ranb

Last edited by RAnb; October 18, 2010 at 05:43 PM.
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Old October 18, 2010, 05:59 PM   #22
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No problem, I hope you get a chance to use them. I haven't done any home anodizing, but am constantly on the hunt for a project that might "require" it.

What are you envisioning in terms of the cause of the weld failure? Just vibration? One fix I could think of would be to slot the outside edges and install several guide rods around the perimeter, welded to each disk. It would be fairly easy to make the guide rods sit flush against, or even index into grooves in the housing. That would supply lateral support while minimizing the chance of permanently lodging the insert into the housing if it gets dirty.

BTW, for those that can't envision it it would look vaguely like this: ()()()() I've seen commercial designs which are similar, so assume it's not a bad idea in theory at least.

It sounds like that guy in the video was stretching the metal on a lathe, I've heard of this but never seen it done. The way I understand it its kind of like throwing a clay pot on a wheel, only with metal.

Press forming metal:
The two types of press forming I'm familiar with are 1) forming the stock between two hard dies (example, somebody over on silencertalk suggested making a die to insert into a loading press to make aluminum cones from soda can bottoms... this would have two interlocking dies); and 2) pressure forming. This involves making a concave female die from a durable material (micarta, wood, aluminum, or plastic all work) and placing the metal between the die and a flexible material like urethane or rubber. Usually this is done on a small hydraulic press. Pressure forces the metal to stretch into and conform to the die.

In my opinion, the second method is easier for the DIY'er, but it's hard to get very sharp corners if that's what you need. You can buy or build a press for not very much money, and the rest of the supplies can be made from your choice of materials in a variety of ways. If you want sharp edges, you can also pressure form first, then finish in a two die system, but that doubles your equipment needs.

Last edited by hal9000; October 18, 2010 at 06:12 PM.
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Old October 18, 2010, 11:14 PM   #23
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Sounds like lots of work. It is worth looking into though.

Ranb
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Old October 20, 2010, 09:17 AM   #24
hal9000
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Like most kinds of metal work, the setup takes longer than the actual forming does. Also, the equipment cost and skills needed are minimal.

You can make a die that produces several items at once which decreases the overall time input. Stamping a single baffle would take longer than making one on a lathe, but stamping 6 at once.... maybe not.

Thanks again for all the advice. I've had some personal issues come up in the last week so I haven't been able to give much time to this. Soon as everything cools back down I'll be back on the path I think
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