Why The Reverse Paradox Tube is NOT a Firearms Silencer

Opinion: Why The Reverse Paradox Tube is NOT a Firearms Silencer
Opinion: Why The Reverse Paradox Tube is NOT a Firearms Silencer

Arizona -(Ammoland.com)- In the previous article about the reverse paradox tube, there was a comment that the BATFE might consider the tube to be a silencer.

Legally, the reverse paradox tube is not a silencer. The law is clear, and there is considerable precedent as to why this is so.

The definition of a silencer, in the law, is in 18 U.S.C. § 921(a)(3):

(24)  The terms “firearm silencer” and “firearm muffler” mean any device for silencing, muffling, or diminishing the report of a portable firearm, including any combination of parts, designed or redesigned, and intended for use in assembling or fabricating a firearm silencer or firearm muffler, and any part intended only for use in such assembly or fabrication.

This is the definition used by the BATFE.  There are three parts to this definition. There is the definition for a complete silencer; a combination of parts designed or intended for fabricating a silencer, and any single part intended only for use in a silencer.

In an article first published in Small Arms Review, written by By Teresa G. Ficaretta, Esq. and Johanna Reeves, Esq., the three parts are explained. The first part is for complete silencers (bold added).

(1) Complete silencer

This portion of the definition covers devices “for” silencing a firearm. Federal courts interpreting this portion of the definition have held that a device can be intended for silencing even if it was not originally designed as a firearm silencer. The best example of such a device is an automobile or lawnmower muffler redesigned or adapted for use as a silencer for a firearm. Automotive fuel filters have also been classified as firearm silencers if they have been modified for use on a firearm.

However, courts have made it clear that devices that diminish the sound of a firearm may not be firearm silencers if the reduction in noise is not the primary purpose of the device. Examples of such devices are chokes, muzzle brakes, flash hiders, or compensators. A cautionary note is in order here, however, as the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), the agency responsible for administering and enforcing the GCA and NFA, may or may not agree that a particular device is a choke, muzzle brake, flash hider, or compensator. ATF’s Firearms and Ammunition Technology Division may determine that the design features of a device make it a silencer despite the manufacturer’s intention to design and market the device as a muzzle brake or compensator. Later in this article we discuss ongoing litigation on this issue.

The second portion the regulation of “combination” of parts was added in 1986, as part of the same Firearms Owners Protection Act which was used to stop further additions of machine guns to the private stock in the United States.

Courts have not had difficulty in prosecuting unassembled part combinations which can be used to put together a complete silencer.

The third part, also added in the 1986 law, as discussed by Halbrook, is for the regulation of any part intended only for use in fabricating or assembling a silencer. This generally prevents the BATFE from classifying baffles or wipes as silencer parts, without evidence of intent to assemble a silencer.

Many legal and common items modify or reduce the report of a firearm.  The BATFE does not hold that anything which reduces the report of a firearm is a silencer. Some people have been prosecuted for devices that did *not* modify or reduce the sound signature, but their intent was to produce such a device.

The intent is a key part of the law.  Moreover, the BATFE understands that some devices reduce the sound signature, even with intent, but are not silencers under the law. The most obvious example is the Metro Gun designed by L. P. Brezny. The Metro Gun is a long barrel extension/ choke much like the reverse paradox tube. It has ports drilled in the side like a compensator.  It screws onto the end of the barrel. The primary purposes of the Metrogun are to reduce recoil, achieve effective patterns, and reduce the sound signature of a shotgun. The BATFE has ruled it is not a silencer. From metrogun.com:

Thirdly note the sound. No blast at ( 72 Db), but a slight crack and dull thud. In effect the same as a full 12 bore suppressor selling for $1000.00 and change. The Metro choke suppressor does not require a BTAF tax fee. No $200.00 dollar tax stamp or paper work required, making for a six month waiting period with the feds either. I sell these systems in most choke thread patterns with a three day turn around.

The primary purpose of the reverse paradox tube is to improve patterns of shot from a rifled bore, thus extending the effective range.

Reverse Paradox Tube Pattern Comparisons
Reverse Paradox Tube Pattern Comparisons

A sight or sights may be added to the tube to increase accuracy, which also increases the effective range. A reduction of noise is not the primary purpose of the device. As with any barrel extension, a reduction of noise is likely.

Metrogun vs Reverse Paradox Tube (btm)
Metrogun vs Reverse Paradox Tube (btm)

Fake silencers are another category of muzzle device which almost certainly modify or reduces the noise of a firearm; they are not generally considered by the BATFE to be illegal silencers.

Here is a fake silencer advertised on gun.rodeo.  It is 11 inches long, it attaches like a silencer, it likely reduces the sound signature a small amount.  That is not its primary intent.

Mac-10 & Mpa .45 Acp 7/8x9, 2 Stage Fake Suppressor, Image Credit: https://www.gun.rodeo
Mac-10 & Mpa .45 Acp 7/8×9, 2 Stage Fake Suppressor, Image Credit: https://www.gun.rodeo

Another barrel extension, recognized as not a silencer by the BATFE, is the bloop tube. These devices are used to lengthen the sight radius. Such devices have also been used on pistols. On .22 rifles, they are called bloop tubes, because they distinctly modify the noise made by the rifle.  That is not their primary purpose, so they are not legally silencers. Here are a couple of bloop tubes produced by Starik, for competition. The longest pictured is about a foot long.

The Starik Carbon Tube. Img credit Starik Shooting Solutions, cropped and scaled by Dean Weingarten
The Starik Carbon Tube. Img credit Starik Shooting Solutions, cropped and scaled by Dean Weingarten

Extending the length of a barrel almost always reduces the report of the firearm. Such an effect can also be produced by using different ammunition.

If a person were so foolish as to wish to convince someone a .22 fake suppressor actually worked, they could substitute Aguila Super Colibri or CB long cartridges while mounting such a fake suppressor, then fire the reduced power cartridges through the fake suppressor. Anyone watching would assume the report was diminished by the device.

Reverse Paradox Tube Controversy

AmmoLand News received some commentary from a lawyer who is an expert witness on firearms and suppressors, expressing concern over the possibility of BATFE prosecutions for making reverse paradox tubes.  The attorney and firearms expert was contacted. We had a conversion. The was much overlap in our areas of expertise. We each learned a bit from the other.

The attorney had never heard of the Metro Gun system or of bloop tubes. He said he will probably obtain a Metro Gun extension for his own use.

The attorney gave me examples where lack of expertise at the BATFE resulted in cases against people who had not actually violated the law. Unfortunately, the punishment by process cost from $10,000 to $30,000, even though they were acquitted.  I forwarded to him some cases I knew about, which he was not aware of.

The primary concern the attorney had, was that some BATFE personnel might arrest and prosecute people, without real technical expertise in what is legally a silencer, and what is not.

In our current situation, where the administrative state runs roughshod over Constitutional limits, it is a legitimate concern.

In my experience, the BATFE does not generally prosecute people when they believe there was no illegal intent.  The number of people prosecuted for federal silencer possession, in the United States, is about 30 per year, according to research conducted for the period 1995 through 2005.

The primary intent of making a reverse paradox tube is clear: to improve the shot patterns of shotshells fired out of a rifled barrel, increasing the effective range. The reverse paradox tube is a long barrel extension/ choke, much like the Metro Gun, except it does not have an explicit purpose of reducing the noise signature.

If the intent is clear, the possibility of prosecution is extremely small.

Reverse Paradox Tube Improvements

I have added an improvement to the original concept: adjustable front and rear sights.

courtesy Dean Weingarten

The sights are mounted on rings sliced off of slip fit couplers for the size PVC tube used.  Such couplers cost less than a dollar. A hole is drilled in the ring and an Allen head cap screw/bolt is self-threaded for the front sight. For the rear sight, a simple eyebolt (for a peep sight) or slotted bolt (for an open sight) can be used. Elevation adjustment works by turning the sight bolt up or down. A tight friction fit facilitates windage adjustments left or right by turning the entire ring.  The sights serve much the same function as an extended front sight serves on a bloop tube, to increase accuracy and effective range.

The entire tube can be rotated slightly left or right so the sights on the tube may be used independently of the sights on the firearm the tube is attached to. Then, the original sights need not be changed to use the tube.

If you make a reverse paradox tube you should pattern it (ten yards is a good distance) to see where it is shooting, and if the addition of a sight or sights is/are desired. For fun, shoot a pattern without the tube, to show the improvement.  Keep the patterns as a reminder for when you next decide to use the tube.  The patterns show the intent for making the tube.

On many forums, commenters seem to believe the BATFE actively seeks out sportsmen to charge for possession of fake suppressors, bloop tubes or long muzzle brakes; if those things happen to reduce the noise from a firearm.

From my reseach it is not happening.

If a person modifies these devices, with the intent to reduce the sound signature of a firearm, they may be arrested and prosecuted. Typical modifications would include additions of baffles, end caps, and or wipes.

The intent is important. Do not modify devices to reduce the sound signature, unless you obtain a Form 1 so that you may make your own silencer, legally.

The purpose of a reverse paradox tube is to improve patterns of shot fired through a rifled bore, and/or to increase accuracy with a sight or sights attached to the tube, to increase the effective range.  Alignment with the barrel is not as important once sights are added to the tube. The increased sight radius improves accuracy.

Such devices are useful in eliminating pests. They are enjoyable for recreation. Perhaps  Mo-Skeet-O or similar games will see a comeback.

If you know of cases where the BATFE prosecuted people for unmodified fake silencers, bloop tubes, or other barrel extensions, please forward them to AmmoLand News. We would like to examine them.

Out of an abundance of caution, AmmoLand News in conjunction with 2AWatch has submitted a Freedom of Information Act request to the BATFE for all information they have on Metro Gun, Metrogun, bloop tubes, and fake suppressors. I will update you on the results of the search request in a future article.

The reverse paradox tube has specific purposes, which are to produce improved patterns of the shot from a rifled bore, and/or to increase accuracy, both of which increase the effective range.  It does not have baffles, end cap, wipes, or an internal ported tube.

The reverse paradox tube is not a silencer.

The author is not an attorney. The above is not legal advice. Anyone making a reverse paradox tube should familiarize themselves with the law, so as to avoid legal difficulties. This article is for educational purposes only. The Author and AmmoLand News have no control over the activities of readers, and bear no responsibility for their actions.

About Dean Weingarten:Dean Weingarten

Dean Weingarten has been a peace officer, a military officer, was on the University of Wisconsin Pistol Team for four years, and was first certified to teach firearms safety in 1973. He taught the Arizona concealed carry course for fifteen years until the goal of Constitutional Carry was attained. He has degrees in meteorology and mining engineering, and retired from the Department of Defense after a 30-year career in Army Research, Development, Testing, and Evaluation.

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If I were to understand the definition correctly, the ATF would charge me $200 to slip a potato over the end of my gun to lessen the blast.

This seems ridiculous.


Use of a potato as a silencer is 100% illegal, and you will be imprisoned if caught. I would never do it because I have seen first hand how the ATF refuses to apply any level of discretion or common sense when they smell an easy arrest. You say you would do it to “lessen the blast,” and that is what suppressors are intended to do. We really need to get the law changed, but until then save yourself even the remote possibility of a life-destroying prosecution. Peace!


What’s the first and second rules about improvised suppressors? That’s right, ………….


But you wold destroy the potato after use. No evidence.




A 2 liter soda bottle works better, just like in the movie Shooter. (VBG)


I like the idea of a lawnmower muffler. Small, easy to find, and probably easy to attach, with either a pipe nipple with a couple of holes drilled and tapped,or heck, even good old duct tape. I suspect that on a .22 cal. pistol or rifle it would be pretty effective.


All we have to do is want to start making guns as loud as possible and then the infringing gov would want us to put suppressors on them.Reverse psychology…


IDK, I love the idea of having a functioning suppressor on a firearm used for plinking or maybe at a indoor range provided the level of suppression is sufficient to negate the need for in, or over ear protection. Being a firearms enthusiast a bolt action .300 Win Mag chassis rifle with a suppressor certainly carries an appeal. Probably enjoy looking at it on my wall every bit as much as firing it in the desert somewhere. But for all practical purposes I cannot think of any scenario where $1000+ for the device, plus $200 for Uncle Sam just because… Read more »


There you have it folks, it is why “Shall not be infringed” was a simple explained article and easy to understand. No strings attatched.


Interesting that the 2 stage fake suppressor in the photo above sports a vertical hand grip on a pistol. That is a no no unless it is a SBR.


From what you can see of the stock, it appears to be a standard milspec ar stock.

Pa John

“The terms “firearm silencer” and “firearm muffler” mean any device for silencing, muffling, or diminishing the report of a portable firearm”… Alrighty then, so set up some large caliber / subsonic semi-auto firearms around the house that are stationary, non-portable, as in permanently attached to swivels on non-movable stands, so they are no longer “portable”, and then silence them to your hearts content without breaking the law! Prepare to protect your ears and not even wake the neighbors while mowing down waves of attacking hordes QUIETLY, from behind well protected walls. (I wonder if simply permanently attaching a length of… Read more »


The black letter law is clear that this isn’t a suppressor, just like the black letter law is clear that a bump stock isn’t a machine gun . . . oh, wait . . .

Use at your own peril, I’ll pass.


Where can we purchase a reverse paradox tube? I have a Tarsus Judge 6” delver that can shoot a .410 shell. Anyone?


“Reverse Paradox Tubes”? Just about as stupid as “Solvent Traps”. You folks have WAY too much time on your hands!!! Get back to work!!!


Not sure what you mean archmark. These are valuable tools, and are in no way connected to homemade silencers. I just had to take care of a chipmunk that was eating the corn planted for the year in the garden. With one of these tubes, the job would have been much easier.


Do you really not see the difference, or are you just trolling?


I haven’t worked for wage in over seven and a half years. I think I’ll pass if it’s just the same with you. I did just go buy $ 500.00 dollars worth of powder and primers so there was a little effort involved in that. Now it is time to shampoo the carpet. Some effort there too. Hi Ho, Hi Ho, it’s off to “work” we go…..……