Please don’t call SureFire’s latest “muzzle devices” a sound suppressor.  Cans they are not, even though they do reduce the decibels of a gunshot.  Elementary suppressor science— that pertaining to a cartridge’s gas volume and a suppressor’s internal volume— is violated by the California-based manufacturer of high-performance tactical illumination tools with their new Mini and Micro models, but the designs are an intentional compromise of sound reduction in exchange for size and weight.

SureFire has always manufactured products based on operator input, and the Mini and Micro models are classic examples of this philosophy.  An elite unit within the Special Operations community approached SureFire’s Barry Dueck, director of the Suppressor Division, and requested a muzzle device that would cut muzzle flash on a 10.5-inch Mk 18 while maintaining about the same noise reduction of SureFire’s trademark K-can (part number FA556-212).

Of course these operators aren’t running 14.5-inch M4s.  They employ either 10.5 inch Mk 18 SBRs or something even shorter.  Black ops being what they are, you never know for sure what the intended application of a short-length suppressor might be— but the Micro would definitely not ride on an M4.

What we do know is that the weapon’s overall length was the main driver in the development of the Mini and Micro models, coupled with flash elimination for night operations.  Reduced weight would be a very much foreseen consequence, resulting in faster target-to-target tracking and improved handling in an MRAP.

SureFire’s latest Mini and Micro models join the company’s previous lightweight champ, the model FA556SA, cutting substantial weight and overall length: (L to R) FA556SA tips the scales at 10 ozs. while the Mini comes in at 14 ozs. made of Inconel and 8.0 ozs. in titanium, lighter than even the Micro model, 12 ozs. and made of Inconel.

But at what price?  The OSHA “safe” level for short-duration noise is 140 dB.  It turns out that the Micro at barely over 4-inches overall nips the sound wave of M855 ammunition from a 10.5-inch barrel to 148 dB while the Mini gets it down to 141 dB, just a hair over the 140 dB “safety ceiling.”

Does it matter?  Not really.  At least not to the guys who specified they want to barter noise for size.  An unsuppressed round of M855 measures about 170 of Mr. Bell’s eponymous units.  If a fully suppressed M4 clips the sound down to the low 130s, a gunshot from an SBR with a Mini or a Micro in the low to high 140s is not much worse than the cymbal clap at the end of the Star Spangled Banner.

The Mini comes in two materials, Inconel alloy or titanium alloy.  Inconel is a highly durable steel that’s popular with many suppressor manufacturers.  Inconel is a brand name of Special Metals Corp. and comes in a variety of formulations, all of which are oxidation and corrosion resistant in extreme environments.  The best attribute of Inconel is that when it’s heated, it forms a thick, stable, passivating oxide layer that protects the material.  Inconel maintains its integrity at extremely high temperatures – and suppressors get sizzling hot in a hurry.

Titanium is an element (atomic number 22) that is known for its strength-to-weight ratio.  It comes in more than two dozen commercial alloys and is a prime component in the aerospace industry.  The best thing is that it’s light as a feather yet strong as an anvil, so the SureFire Mini made of Inconel weighs 14 ounces while the same exact model made of titanium barely tips the scales at 8 ounces.

The tradeoff?  Titanium is expensive, it’s hard to machine and it’s not as long-lasting as Inconel.  The payoff?  A muzzle-heavy rifle is hard to swing dynamically from target to target but a Mini or Micro equipped AR swings like a dream.

The Mini and Micro feature the latest SureFire improvement to its lock-ring system of attachment to a mated muzzle brake adapter.  One could call this the Gen 3 lock ring as it’s the third distinctive method used since SureFire first manufactured a suppressor in 2002.

The first lock ring utilized a system similar to a Walker liner lock on a folding knife.  A metal tab “snapped” into place to prevent the locking ring from unloosening from the threads on the rear of the suppressor.  Gen 2 eliminated the spring tab and replaced it with a press-to-unlock tab.  The latest version that I call Gen 3 features an improved release latch with a lower profile.  This lower profile also decreases the chances of the latch accidentally releasing, should it be bumped hard, dropped or knocked around.  The new lock rings also feature user-replaceable parts so, should a repair ever be necessary, it can be made directly by the operator or armorer rather than requiring the entire unit to be sent back to SureFire.

“These (lock rings) are also all backwards-compatible,” says Dueck.  “So you can have an old adapter and a new suppressor, same model, and it still fits.”

This is particularly good news for armorers in military and law enforcement where SureFire suppressors have been making impressive inroads.  One example: every Marine Corps M40A5 sniper rifle now comes standard with a SureFire MB762SF adapter and a SureFire FA762SF suppressor.  Not that SureFire makes a .308 caliber Mini or Micro, but the point is that their cans are gaining kudos wide and far in the U.S. military.

In fact, sources within the industry tell this author that SureFire product will soon be replacing AAC product as the issue-suppressor for FN’s SCAR system.  The competition has led to some contentions that will be played out in the end-user community and final contracts.  When the smoke clears, SADJ will bring you the report.

SureFire has been issued patents for its repeatable barrel attachment method of a muzzle brake/adapter interfacing with the suppressor via an eccentric locking ring that sucks the two together with in-line tension.  Threaded-on attachment methods are useless for securing two parts; threads serve only to align, not fasten.

The primary benefit of the SureFire attachment method is that a repeatable point-of-aim/point-of-impact is achieved.  Most suppressor brands cannot hold a repeatable zero from suppressed to unsuppressed, or even from attachment to removal to attachment again.  Not SureFire.  The engineers that developed high-intensity WeaponLights have also worked out how to make a rifle hold its zero – with or without a can.

SureFire suppressors are not inexpensive;  a SureFire can’s street price is around $1,300, not including a muzzle brake/adapter.

Surefire Blank Safety Device
How many times have tragedies occurred that seemingly “can’t” happen? The U.S. military adheres to strict safety protocols when training with real weapons and blank ammunition, yet someone is killed when a live round sneaks into a blue-on-red training exercise.

SureFire has addressed the problem of live ammunition in a blank-firing environment with a “safety suppressor” that looks just like the company’s real sound suppressors, but comes with a special “bullet capture” chamber to prevent a live round from launching a bullet in training environments.

Dubbed the BSD or Blank Safety Device, the bright yellow tube is made of solid aluminum with a steel “blow-out valve” to vent high pressure gases as the unit captures up to three projectiles. If you fire three live rounds into the BSD and still haven’t figured out that something is very wrong, the next one will damage your rifle and render it inoperable.

It works like this: the bottom of the BSD features an exhaust port sealed with a membrane. Should a live round enter the BSD, the gas pressure blows out the membrane and the shot is substantially louder than a normal blank. This provides an audio clue to the shooter that something is very wrong, coupled with a jet of flame from the bottom of the BSD to alert others that a live round has been triggered.

The BSD fits on any SureFire muzzle brake/adapter and can be fitted with a replaceable orifice to fit a standard GI birdcage.

Affable, cheerful and humorous, the doctor appears to be a wonderful real-world example of Marcus Welby – except he carries a gun. His name is Dr. Phil Dater and it might have been his fascination with how things work that led the curious physician to first experiment with sound suppressors in the 1950s, and later in the basement workshop of a hospital where he worked.  Given his interest in firearms and his understanding of the scientific method – form a hypothesis, test it through repeatable experimentation and modify accordingly – Dr. Dater naturally took to sound suppressors and has been involved in many of the seminal sound suppressor companies in the modern era.  Of all the arcane areas of firearms, suppressors are the most firmly rooted in a “trial and error” design processes because no amount of computers can possibly calculate all the variables at work when a gunshot erupts.

Suppressors have intrigued me too, which is how I’ve come to be sitting in the front row of Dr. Dater’s two-day class on Suppressor History, Technology & Testing conducted at the GSA training contractor, Long Mountain Outfitters in Henderson, Nev.  The class is open to anyone, although Dr. Dater insists his students be vetted to assure no one of dubious motivation sneaks in.  His information is protected by ITAR regulations, so only DoS qualified foreign nationals can attend and Dr. Dater understandably prefers his competitors to not attend.

Our class consists of firearms engineers, enthusiasts who want to learn what they can; suppressor dealers who want to enhance their sales ability, and several U.S. government employees from various military branches.  Unbeknownst to me at the time, a celebrity is sitting in the back of the room, Pulitzer Prize winning author Stephen Hunter.

Dr. Dater makes a fine adjustment to his Larson-Davis 800B sound measuring instrument after having calibrated it with a known frequency from a special tuning device. Temperature, barometric pressure and altitude all affect sound measurements.

Dr. Dater displays an assortment of suppressors – “cans” in the vernacular – and immediately makes full disclosure that he’s one of the principals of Gemtech, a suppressor manufacturer.  He assures us that his class is non-brand-specific, but that he wants everyone to know he has an interest in Gemtech.  “I’ll try not to flog our product as this is not a sales presentation,” he says amiably.

Suppressor Background
Suppressors date to the turn of the century when Hiram Percy Maxim, son of the legendary machine gun inventor of the same name, started the Maxim Silent Firearms Company.  Our class later tests one of Hiram’s original cans and surprisingly performs right up with “modern” designs.

Dr. Dater mentions some other famous suppressor inventors such as Mitch Werbell, Mickey Finn, Reed Knight and Doug Olson, pointing out that all of their designs came from trial-and-error experimentation along with scientific and engineering principles.  It’s clear he has respect and admiration for these pioneers of silence.

We then jump right into the subject.  Dr. Dater explains the basic science of sound.  Sound is a form of over-pressure which is measured with a ratio of pressures – reference pressure to measured pressure – expressed in a unit of measure named for another well-known experimenter of sound transmittal: Alexander Graham Bell.  The unit is called a decibel.

A gunshot, Dr. Dater tells us, is the sudden release of hot, high pressure propellant gases exiting from the muzzle of a firearm.  A second component of a gunshot, the sonic crack, is caused by the bullet travelling faster than the speed of sound, like the sonic boom of a high-speed jet.

Going back to high school physics, Dr. Dater asks the class how to decrease pressure.  I brush back the fog of time and remember that pressure is equally affected by temperature and volume.  “That’s right,” says Dr. Dater, “If you lower the temperature and increase the volume, pressure decreases.  In its simplest form, that’s all a can does to reduce sound – decrease temperature, increase volume.”

The classroom portion of the suppressor class was held in the headquarters of Long Mountain Outfitters in Henderson, Nevada. The gentleman at the rear of the room is best-selling author Stephen Hunter, creator of a series of Bob The Nailer novels that are renowned for their firearms and shooting accuracy.

Now comes the technical part.  Sound is not only a factor of loudness – decibels – but also of duration.  Think of tapping your car horn versus an ambulance blaring its siren.  The duration of the siren is more damaging than the short toot of a horn, even if they’re the same number of decibels.  This leads to a discussion of what constitutes “harmful” levels of sound, which in turn brings us to the U.S. military’s definition of sound measurement as defined in Mil-Std 147 4D.

We will hear a lot more about Mil-Std 147 4D before the class is over.  It’s the gold standard of suppressors, the only acceptable measurement of performance.  Because the scientific method of trial and error is so important to suppressor testing, having a defined standard like Mil-Std 147 4D is imperative.

Reasons for Suppressors
Thanks to Hollywood, suppressors are widely perceived as only being used by assassins.  It may be true that some cans have been used to snipe an enemy (we dropped suppressed .45 ACP rifles to the Resistance during World War II) but in today’s tactical climate, the suppressor has far more benign uses.

With law enforcement switching to patrol rifles such as Colt Commandos, the number one reason for a suppressor is to protect the shooter’s hearing.  Additionally, cans serve to enhance command-and-control, confuse or deceive the target, to shoot out street lights or guard dogs on drug raids, to conceal the origin of the shot, muzzle flash minimization and a host of other tactical reasons.

Suppressors are a restricted item in the U.S. because when the National Firearms Act was passed in 1934 in the middle of the Depression, where Fish & Game determined that suppressors were used by poachers trying to feed their families, as well as an unfounded Hollywood stigma that suppressors were for assassinations.  The Judge Advocate General of the U.S. Army decreed that suppressors are a part of military equipment.  Be that as it may, suppressors can be acquired by paying a $200 federal transfer tax and going through all the Form 4 paperwork associated with NFA weapons.

Or, better yet, make one at home.  Dr. Dater told the class about experiments with seized and home-made suppressors that he performed with properly calibrated sound equipment at the California Criminalists Institute.  First came the oil filter, nothing more than a common, everyday oil filter fitted to the end of a Ruger 10/22.  “That one worked pretty well,” Dr. Dater laughed.  “We got a 22 decibel reduction.”  He tried a sprinkler head with a wadded up piece of cloth inside, a 2 liter pop bottle, a tennis ball can of three balls and, the best of all, a potato.  “The potato worked really well, probably because of the high water content, but the bullet came out with what I’d guess was 30 degrees of yaw.  Very unstable,” Dr. Dater said.