The Firearm That Isn’t: Silencers and the “Loud Bang Theory”

This guest post is based on a paper that was presented at the 2025 Firearms Law Works-In-Progress Conference and reflects the author’s views only. The Conference is held each year on a home-and-away basis with the University of Wyoming Firearms Research Center. This post also appears on the FRC's Forum. 

Guns are loud. Deafeningly so. They have always been. But that isn’t an intentional element of their design. It is simply an artifact of the physics of how firearms function; the rapid expansion and escape of gases from the barrel makes a “bang.”

That loud sound is harmful and can immediately damage the hearing of anyone nearby. Shooters engaged in target practice can wear earplugs or earmuffs to mitigate the damage, but such measures are impractical because everyone else around them must also take steps to protect their hearing. They can also inhibit important communications, like safety instructions. While hunting, where whispers, stillness, and careful listening are essential, implementing those measures is all but impossible. The sound of gunfire can be a nuisance to residents who live near a gun range. The noise, and attendant recoil, can also cause ‘flinching,’ impairing accuracy.

Despite the downsides, the ‘loud bang’ might also have implicit benefits. Perhaps it is “a feature, not a bug.” When it happens in public, it is an immediate, unmistakable, ingrained warning and call for attention. It can raise alarm and activate emergency response. If someone has been shot, it may help bring aid to the wounded. It can warn others that danger may be afoot. Modern public safety technology uses the noise to detect gunfire and notify police. The sound of gunfire might also deter some criminals, who would perhaps shoot their firearms freely if they could do so more quietly but are instead restrained by a louder sound that might reveal their crimes.

Between these pros and cons, lies the “silencer.”^[1] More than 100 years ago, Hiram Percy Maxim introduced a device to the commercial market that could reduce that deafening, signaling sound.

Whether the Second Amendment protects technical progress toward quieter guns, or whether the loud ‘bang’ is an immutable characteristic of firearms, is the subject of my article, The Firearm That Isn’t: Silencers and the “Loud Bang Theory.” To examine the question, I contrast the strikingly divergent cultural and legal experiences of silencers with those of optical sights, or “scopes.” Both have practical utility, and potential for criminal misuse, but their path has not been the same. I attempt to reconcile the disparate treatment, including whether courts have reached textual conclusions about silencers that do not consider whether, but for legal restraint, quieter guns (like better aimed ones) might be the natural evolution.

The Maxim Silencer

Enthusiasm was high for Maxim’s silencer. Scientific American predicted it would be as valuable to military stealth as smokeless powder and camouflage. The jubilance was short lived. Only a month after praising its value for combat, Scientific American clarified that, beyond military use, it considered the silencer a “menace.”

The State of North Dakota agreed. Barely a month after Maxim unveiled his invention, its legislature found that “an emergency exists in that there is now in existence no provision prohibiting the use of a firearm silencer in this state” and passed a law prohibiting them. The State of Maine followed suit less than two weeks later. Other states would impose similar laws in the years to come.

Scientific journals and sparsely populated states weren’t the only ones with concerns. The silencer also met immediate skepticism from some in law enforcement. Within a month of its public debut, Pittsburgh’s Superintendent of Police captured the sentiment that would dominate public perception for the next century when he opined that “the use of the ‘silencer’ will prove disastrous to the peace of every city where precautions against its use are not taken.”

Even if overblown, the concern that some criminals might employ silencers was not entirely unjustified. Almost right away they began appearing in crimes. What is less clear is how often. For this article, I collected decades of contemporary news accounts of crimes involving silencers. Considering the growth of violent crime during the era of the silencer’s debut, public reports of their actual use in crimes were comparably infrequent. But what is clear is that when they appeared, the crimes were sensational. Perhaps that is why they soon began appearing in popular entertainment, too. Silencers remain a mainstay of Hollywood hitmen today.

All this solidified the silencer’s nefarious reputation and led to comprehensive legal restrictions. Interestingly, both the National Firearms Act of 1934 and the Gun Control Act of 1968 legally define silencers, in and of themselves, as “firearms.” Silencers are not firearms, of course; they cannot be used to shoot independently. Nonetheless, as “firearms,” they are subject to the same regulations as actual firearms. A person prohibited by law from possessing a pistol or rifle is also prohibited from possessing a silencer, even if it is not attached to such a weapon. The NFA additionally imposes a strict regulatory framework under which a silencer must be registered and a tax paid. (On July 4, 2025, the President signed a bill that will reduce the tax from $200 to $0, but the other regulatory provisions remain intact). The penalty for simply possessing an unregistered silencer is stiff: up to ten years in prison. Despite the legal hurdles, silencers have lately experienced a renaissance. The number of lawfully registered silencers has exploded, thanks to increased advocacy and awareness of their benefits.

Scopes

But silencers aren’t the only innovation with both practical utility and criminal potential. Besides being loud, firearms weren’t always accurate either. Hitting one’s target is a fundamental, functional aspect of using a firearm. The technological advancements of “rifling” (cutting twisting grooves in the interior of a barrel to impart a spin on the projectile) and the addition of front and rear “sights” helped improve accuracy and aim, respectively. But the effective range of firearms improved even more with the invention of telescopic sights, or “scopes,” which provide a magnified view and precise distant aiming.

Like silencers (and guns themselves), scopes have obvious potential for criminal misuse. A scope increases the effectiveness of a firearm by allowing it to be fired accurately from greater distances. This may help a criminal kill a target, who he might not otherwise be able to approach, from far away. The distance may also help the criminal evade detection (just as a quieter gun might). This threat is not theoretical. Some of the most consequential crimes in American history have been facilitated by rifle scopes. Several are so notorious, there is little need to describe them in detail here. JFK. MLK. The Beltway Snipers.

Silencers, Scopes, and the Second Amendment

Despite the obvious parallels between silencers and scopes for facilitating surreptitious crimes, they have experienced vastly different public perceptions and legal treatment. Unlike silencers, scopes are essentially unregulated (export controls notwithstanding) and enjoy a permissive legal and cultural reception. They are not maligned and there are no calls to banish them. As such, there is virtually no case law assessing whether scopes, or the technological evolution they represent, are protected by the Second Amendment. (A few local jurisdictions restrict “laser sights,” which function differently than scopes, and one U.S. District Court found one such law constitutional. Interestingly, Chicago’s ban on laser sights is contained in the same statute that prohibits silencers.)

The harsh legal treatment of silencers, however, has led to many prosecutions and has triggered challenges under the Second Amendment. The resulting judicial opinions show that when it comes to silencers, the law wants to have its cake and eat it too. Despite how federal law explicitly treats silencers, even standing alone, as firearms, courts that have considered challenges invariably find that they are not protected by the Second Amendment because, they say, they are not “Arms.”^[2] They treat them as optional “accessories,” unprotected by the Constitution. They are not essential.

But these courts have not considered whether they are protected instead as technical improvements that represent a stage in the natural evolution of firearm technology. The Second Amendment must protect some technical innovation in firearms because, like the law itself, firearms are not “trapped in amber.” The guns protected by the Constitution today are descendants of the ones that existed in 1791, not their twins. They have evolved and the Constitution protects that evolution.

In District of Columbia. v. Heller, the Supreme Court observed that “[s]ome have made the argument, bordering on the frivolous, that only those arms in existence in the 18th century are protected by the Second Amendment.” Although we look to history for meaning, “the Second Amendment extends, prima facie, to all instruments that constitute bearable arms, even those that were not in existence at the time of the founding.” The Court has repeated this point many times (in Caetano v. Massachusetts; New York State Rifle & Pistol Association, Inc. v. Bruen; and U.S. v. Rahimi). In Rahimi, Chief Justice Roberts added that it would be a mistake to apply the Second Amendment’s constitutional protections “only to muskets and sabers.” But we didn’t go from “muskets and sabers” to AR-15s and semi-automatic pistols overnight. Firearms have evolved since 1791. That means the Second Amendment must also protect that evolution.

Guns have improved in almost every way since the Founding. They are lighter, more durable, more reliable, more accurate, and better aimed. But they aren’t any quieter. Using the vastly differing treatment of silencers and scopes, culturally, legally, and precedentially, as a reference point suggests that something other than the potential for criminal misuse must be responsible. That returns us to the loud bang.

If the courts are right that the Second Amendment does not protect silencers, then this leads to the inevitable conclusion that the “loud bang” is the unspoken reason why. They are saying that it is an essential characteristic of firearms, like the boom of a firework or the clap of thunder, a thing that cannot be separated from the instrument that makes it. A signal that the Constitution does not protect suppressing. An effect that the otherwise steady march of technical improvement cannot dampen. Innovation can make better-aimed guns, but not quieter ones.

The practical utility of the sound of gunfire, for detection, warning, response, awareness, implicitly explains why courts and some policymakers treat silencers with such skepticism, even when a century of history suggests they are rarely used in crimes, and do not actually “silence” firearms but only reduce the noise to a level that doesn’t risk injury. Keeping guns loud effectively prioritizes public safety benefits over personal health and safety benefits of noise reduction.

This principle that firearms must produce a loud, detectable noise is not explicitly stated in the law or in judicial opinions, of course, which instead parse distinctions between “accessories” and “arms.” But that is the practical effect. This strains constitutional coherence. If the right to keep and bear arms extends to the ways that firearms naturally evolve (and the Supreme Court says it does), then surely it protects that evolution when it enhances safety, rather than increases lethality. The “Loud Bang Theory” provides an unarticulated, underlying rationale for why silencers have so far been treated differently.