James Bond movies aside, sound suppressors in the real world are not made for assassins. First of all, silencers are not silent. There is always the crack of the bullet as it breaks the sound barrier. But even if you're using specially loaded subsonic ammo, you'd still have at least the sound level of a loud handclap from the gun's chamber, even with a well-designed suppressor. Besides, name one assassin who ever used a silencer since Hiram Maxim first invented a sound suppressor for firearms around the turn of the century. Even in military circles where suppressors are legally obtainable, the most famous sniper in U.S. military history, Carlos Hathcock, worked with an unsuppressed Winchester Model 70. The fact is that there are more myths and mistruths floating around about suppressors than perhaps any other item of personal weaponry. For instance, if I told you that a Remington 700 in .308 shoots a half-inch at 100 yards with 168 gr. Federal Match, what do you think would happen to accuracy if you added a suppressor to the gun? Better or worse group? And what would guess would be the affect on the bullet's velocity if you added a suppressor to that 700? Faster, slower or no change?

The answers may surprise you. But before we reveal them, we need to introduce the subject of our discussion, the newest suppressor on the market. It represents a quantum leap forward in suppressor technology, something you might expect when you learn that it's from SureFire, the company that creates all of its products with "cool science." It's the idea that if you put engineering above other mundane considerations, like sales projections and marketing studies, that you'll get a way cool product that will sell itself on the strength of being better than anything else in the field. Cool science worked with tactical illumination tools, and now it's working with suppressors. SureFire entered launched its new Suppressor Division in 2002, but the first working production model, called the M4FA, was not finalized until 2003. Made for the 5.56mm NATO round and optimized for use on the Colt M4 rifle, the M4FA is the essence of cool science.

"We turned loose our Cal Tech Ph. D on the project," quipped Barry Dueck, director of the SureFire Suppressor Division. "Our engineers drew on their expertise with high-temperature alloys and exotic metals to design a suppressor that is smaller and lighter and more durable than anything else out there." Dueck, who was the military sales manager at SureFire before being promoted to director of the Suppressor Division, has extensive experience with suppressors. He formulated a design for the interior configuration of the baffle system in the new M4FA. Brooke Smith, SureFire's Firearms Control Officer, also had a background with suppressors, and he contributed to the baffle configuration for the suppressor. Akin to the wing design on an airplane, the baffle design and interior dimensions of a suppressor are crucial to the performance. Noise reduction can vary significantly by the number, shape, size and form of the baffles. Ever since Maxim's first patented design of over 100 years ago, silencers have employed a series of baffles inside a hollow tube to muffle or retard the noise from a gunshot. The arrangement of the baffles and their alignment with the bore is basically what determines how well your suppressor performs.

Most cans have been made by trial and error by individuals with little or no scientific background. One manufacturer actually admitted that he had "no idea" how or why his design worked, only that he'd "tweaked it" until it seemed to function the best. Not exactly cool science! The SureFire way to test a suppressor design is to measure it scientifically. Smith launched a research project to find the best sound and vibration measuring equipment. Meanwhile, Dueck contacted a government agency that tests suppressors and asked what device they used. The answer they both derived was that a highly sophisticated sound measuring system could be purchased from Denmark. The device was made by Bruel & Kaer. Asking price: $26,000. SureFire bought one. Now accurate scientific measurements could be made as different alloys, materials and designs were tested. But first Smith went to "sound school" with the engineers from Bruel & Kaer, working many late nights to learn the intricacies and subtleties of not only how to operate the esoteric software that drives the sound machine, but also how to interpret the data intelligently. After months of work with the B&K device and picking the brains of the Danish engineers, Smith emerged as arguably the most knowledgeable person in the firearms industry on how to measure the noise of a gunshot.

Sound Science Made Simple
The design went through several iterations as the sophisticated Danish sound machine told Dueck and Smith precisely what baffle arrangements worked better than others. Sound reduction, they found, was also dependent on atmospheric conditions. "We'd get one reading one day and another the next. Barometric pressure, temperature and humidity were all having an effect," Dueck said. "We had to test a given design a number of times under different conditions to get a meaningful reading." After finalizing on the optimum design, the noise attenuation was rated at between 27 and 30 decibels (dB), reducing the sound of a 5.56mm to a handclap from an ear-splitting crack. To appreciate how significant a reduction 30 dB represents, we need to understand how sound is measured. Most noise sources are measured in terms of intensity, or strength of the sound field. The standard unit of measure is 1 dB which is the amount of sound that is barely audible to the average human. The decibel scale is logarithmic, meaning that each unit is 10 times that of the preceding one. For example, a noise source measuring 70 dB is twice as loud as a source measuring 60 dB and four times as loud as a source reading 50 dB. A barely audible whisper measures 10 dB and a speeding express train rates 100 dB, although the train generates 10 billion times as much sound energy. This misleading difference can also be seen in earthquakes using the Richter scale, which is a logarithmic scale like the decibel scale. A magnitude of 5.3 on the Richter scale is a moderate earthquake, while a devastatingly strong earthquake has a magnitude of 6.3. Thus, like sound, a small difference in value actually means a great difference in intensity. "Reducing a gunshot by 30 dB makes it 16 times quieter. To put it another way, the sound of the action cycling - just the bolt clattering back and forth - is louder than the round firing," Dueck explained. "Even a 14-inch barreled M4 can be safely fired indoors without damaging your hearing," the director of the Suppressor Division added. "This is a very significant tactical advantage."

Point Of Impact Shift
SureFire tested other brands of suppressors during the R&D phase of testing and Dueck discovered something rather disturbing. While most of the better made cans offer roughly the same noise reduction, they vary dramatically in their accuracy, durability and - most importantly - their affect on the bullet's point-ofimpact. "Optimally, what you want is no change in the point-off-aim, point-of-impact when you add a suppressor." Dueck said. "What we found was pretty bad. The current-issue SOCOM can shifts an average of 4-inches at 100 yards, which is terrible. Some military operators told us we were lucky - some of their cans were more like 12-inches of shift." What this means, of course, is that you're off the target at 50 yards. "Unacceptable," scoffed Dueck. "Totally unacceptable." Dueck and his team knew they would not put the SureFire name on anything with such shoddy performance, so a key design goal was to produce a suppressor with minimal and repeatable point-of-impact shift from unsuppressed to suppressed. "Putting a suppressor on the gun is not just a sound issue. Can you take that suppressor off and still keep zero?" Dueck said. The first production run of the M4FA suppressor averaged less than one MOA of shift in a batch of 100 suppressors that were tested before delivery to a special operations group. "A shift of one minute is acceptable," Dueck observed.

Size And Accuracy
Equally important to the shift issue was the matter of accuracy, which harkens back to a question asked at the beginning of this article: how does a suppressor affect accuracy? Improve it, worsen it or make no difference? Assuming a properly designed suppressor like the M4FA, the answer is accuracy improves - groups tighten up, sometimes significantly, sometimes modestly. The reason is that a well-designed suppressor acts like the world's best muzzle crown, releasing the bullet with perfectly even pressure on the base of the bullet. Competitive rifle shooters know how important the muzzle crown is for this very reason. The more stable the bullet leaves the barrel, the more stable it carries in flight. A suppressor enhances accuracy by taking away the turbulence of uneven gas pressure. To answer the other question posed at the beginning of this article - what affect does a suppressor have on muzzle velocity? - the answer is again a bit of a surprise. A suppressor increases the bullet's velocity, by about 30 to 50 fps, because the extra length of the can behaves somewhat like additional barrel length. While the gas seal behind the bullet is not bore-size tight, the hole in the suppressor is only a few thousandths over bullet diameter, allowing a bit more opportunity for the propellant gases to accelerate the projectile. By comparison, an extra 5" of rifled barrel might add 200 fps to 300 fps while 5" of can will only up the velocity about 30 to 50 fps. Still, any increase is an increase. Speaking of length, the SureFire M4FA adds only 3.75" to the overall length of the weapon, compared to over 6" for the currently issued SOPMOD can. The bulbous length of the current issue can alters the weapon's point of balance and makes it unnecessarily unwieldy. Combined with the extra weight of the unit, the SOPMOD can adds up to a heavier, bulkier, longer can than the lightweight M4FA. And so now the M4FA suppressor design was optimized. The point-of-impact shift was negligible, the affect on accuracy was beneficial and the terminal ballistics of the cartridge were actually improved. Only one final test remained, and it was brutal.

Torture Testing
Suppressors reduce gunshot noise in a complex manner that crosses many scientific bridges, from the study of flow dynamics to the analysis of sound wave behavior. But for a very simple explanation of how a can works, it's this: a suppressor converts sound energy to heat energy. Suppressors get hot. Alabama pavement hot. White hot. Glowing like molten metal hot. Using a high-speed digital camera, SureFire engineers photographed a prototype suppressor glowing whitehot to the point that you could see the baffles through the steel exterior tube. Using a special probe to measure the temperature, they noted the temperatures and adjusted their high temp alloys accordingly. Intense heat is extremely damaging to metal, but a suppressor has to withstand more than just blast furnace temperatures. Additionally, there is unburned powder residue and carbon granules that exit the rifle muzzle. These super-heated particles hit the rearmost baffle in the suppressor like a turbocharged bead blaster. Lesser makes of cans can only withstand a limited amount of such punishment before the peppering of the hot particles cuts the rearmost baffle. Typically the hole in the center of the baffle erodes away, becoming larger. Then the blasting particles sear into the next baffle and next and the next. Soon the concentric hole for the bullet's passage is non-concentric, the sound suppressive design is compromised and can no longer function. In catastrophic failures, bullets erupt out of the side of the can, zinging wildly into who knows where. Because of the extreme strength and durability of the high temp alloys that are used in the M4FA, Dueck was able to reduce the weight to a mere 17 ozs. while increasing the longevity. By comparison, the average .223 can in the industry weighs 24 ozs. "We fired 1,500 rounds on full auto as fast as we could stuff 30- round mags into the gun. We totally ruined the barrel, but the suppressor was barely even marked," Dueck said.

Sadly, the U.S. military issues a can that can't come remotely close to such performance. The average service life of the current issue SOPMOD can is barely 5,000 rounds, according to a highly placed operator in a Special Forces unit who spoke to Combat Tactics on condition of anonymity. "It's a piece of crap, but the manufacturer has political connections, so that's why we're stuck with it," the source said. The SOPMOD specification is for 10,000 to 15,000 rounds of service life. SureFire guarantees a service life of 30,000 rounds with its M4FA suppressor. "Honestly, we haven't been able to make one fail yet," said Dueck. "But we're being conservative and rating it for 30,000 rounds." The difference is in the high-temp aerospace alloys that SureFire uses in the suppressor, Dueck explained. "Durability is a huge consideration," the director of the Suppressor Division added. "I don't know of anyone out there who can compete with us on durability. We've put 1,500 rounds through a suppressor in 30 round bursts, just speed reload after speed reload. We broke the first M4 we tested like this on the fifteenth consecutive magazine, so we took the suppressor off, stuck it on another M4 and kept on with the test. Basically, we wrecked two guns and the suppressor had absolutely nothing wrong with it."

Quick-Attach Mechanism
Having perfected a rugged and durable suppressor with negligible zero-shift, the final piece of the puzzle was the attachment mechanism. The goal was to design a replacement flash hider that incorporated a special interface for the suppressor. Needless to say, the replacement flash hider could not worsen the flash signature of the standard-issue Colt bird cage. Additionally, Dueck wanted the attachment to be as fast as possible, which precluded any sort of screw-on threading. "There are lot of problems with threads, besides just plain being slow," Dueck said. Dr. John Matthews, the founder of SureFire, came up with an ingenious solution - an eccentric ring that locks around a shoulder on the replacement flash hider, utilizing dual bearing surfaces for precise alignment with the bore. Simple as simple can be, you just drop the can on, twist the eccentric lock ring, done. That fast. To remove the suppressor, there is a small metal tab similar to a liner lock on a folding knife. Depress the locking tab with a finger, undo the lock ring and the suppressor pulls right off. That fast. "We've applied for a patent on the Fast-Attach eccentric lock ring design," Dueck noted. "It's that slick, we think we can patent it." With that, the project was complete and SureFire entered the suppressor market. Almost immediately, the design was hailed as the most significant breakthrough in suppressor technology since the military first began issuing cans to the Special Operations community. The enthusiastic reception from both military and police was a gratifying reward for Dueck, Smith and the new team at SureFire's Suppressor Division.

Cameron Hopkins was the editor-in-chief of American Handgunner,GUNS Magazine and Shooting Industry for 17 years before joining SureFire.He is the vice president of sales and marketing for SureFire.