The NRA writes [via ammoland.com]: Suppressors are devices that, when attached to or integrated into a firearm, reduce the amount of noise and muzzle flash produced when the gun is fired. Most people familiar with firearms have seen some variant of a suppressor, usually a tubular device affixed to the barrel of a firearm. We know that suppressors work – as evidenced herehere and here – but it makes us wonder, how? How could a tube of metal manage to quiet down the sound of a gunshot?

Science and engineering working together, of course!

We know that guns make a variety of sounds when fired, the most pronounced being the loud “boom” that occurs when the projectile exits the barrel. This is due to the rapidly expanding propellant gases that power the bullet forward out of the barrel from the chamber. That instant pressure and temperature change creates the explosive sound, not to mention the bright, fiery flash of light from the muzzle as the bullet leaves the bore.

Think of a time you might have opened a bottle of champagne. Immense pressure from the contents collects beneath the cork. When you remove the cork, you’re likely to hear a distinct “pop,” a result of that backed-up pressure being released at once, usually propelling the cork quickly out of the bottle. This is the same concept that applies when expanding gases exit the muzzle of a firearm.

The inside of a suppressor most commonly will have two sound-reducing parts: first, an expansion chamber near the barrel will cause the gases to expand and lose some energy, and second, the aforementioned baffles, which are essentially small barriers with holes in them that allow the projectile to safely pass through the suppressor while deflecting and slowing the expansion of the gases.

The suppressor internals are precision-engineered to accommodate particular calibers and applications. The number, construction, and geometry of the baffles and chambers vary to suit the application of a particular suppressor.

Silencer Parts Img SilencerCo
Silencer Parts Img SilencerCo

Some modern suppressor manufacturers have implemented advances in technology by creating suppressors that only use baffles, while others boast only an expansion chamber. Computer-aided design and CNC machinery have fostered the development of the monolithic core suppressor. In “monocore” suppressors, the internal support structure and baffles are milled from a single piece of metal that can be easily removed from the tube for cleaning (especially important for rimfire suppressors).

The reduction in noise is made possible because the suppressor’s chambers give gases a larger, contained space to dissipate and cool before exiting the firearm. Suppressors have massive volumes compared to the tight tolerances of gun barrels, typically 20 to 30 times greater.

Silencer Parts Photo courtesy Guns com

With all that room to fill, the pressurized gas that follows the bullet expands into the chambers, which dramatically decreases the pressure. As a result, when the bullet finally exits the suppressor, the lower pressure significantly softens the report of the shot. This quieted report is clearly easier on the ears, and can help suppressor users maintain advantages while hunting or shooting recreationally.

Additionally, the reduction in pressure eliminates a great deal of the bright muzzle blast, which is due to the remaining unburned powder combusting and mixing with ambient air. The baffle chambers of the suppressor capture much of that unburned powder too, reducing the intensity of the muzzle flash. Lastly, capturing a good deal of that pressure in a suppressor helps reduce muzzle rise and felt recoil because the gases “push” forward on each baffle in the opposite direction of recoil.

It’s important to remember that suppressors, true to their moniker, suppress the report of a firearm rather than entirely eliminate it. Users must be sure to evaluate their particular firearm, ammunition and suppressor combination to determine if additional hearing protection is appropriate.

24 Responses to Guns for Beginners: How Suppressors Work

  1. The ever present and sharp supersonic crack from .223 AR15 and large calibers will disappoint first time users.

    Most impressive results when using suppressor and sub-sonic ammo (such as 22LR, 300Blackout, and certain pistol calibers)

    • I was noticing how much they sounded like shooting a .22. One of my favorite things about shooting full-powered .22lr is how the sound mostly consists of that supersonic crack.

  2. If we are unfortunate enough to get the HildaBeast rammed down our throats the same way the (Un-) affordable ‘Care’ Act was, we need to seriously consider getting the ‘Hearing Safety Act’ piggybacked to some legislation that the Progs consider must-pass.

    Being Progressives, there’s gonna be a (Metric or SAE) sh!t-ton of laws they are gonna want crammed down our throats.

    There’s a good chance we can force their hand on this, safety being ‘for the children’ and all…

  3. When are suppressor manufacturers going to start selling suppressors for reasonable prices?

    First of all, there is no justification for charging several hundred dollars because the material and manufacturing costs are in the range of $10. (A simple, effective suppressor requires 100 year-old simple machining technology.)

    Second, and most importantly, we would have much stronger footing if we take fedzilla to court when a suppressor costs $50 and its tax is $200 (400%). A 400% tax is clearly designed to prohibit acquisition of said item and a tacit admission that fedzilla is trying to ban something that they know they do not have the Constitutional authority to ban.

    As it stands, many courts could claim that the present $200 tax on a $1,000 item is “reasonable”. (The tax would be something like 20%).

    • Do you know how much CNC machines cost? Do you know how much the tooling to produce products costs?

      FYI, for those of you who look at some of these monocore suppressors, here’s my guesstimate on the lineup of machines:

      – You’ll need a CNC vertical mill, with either 4 or 5 axes capability, and you’ll need a pretty straightforward CNC lathe, orrrr….

      – You need a CNC lathe with live Y-axis tooling.

      Either way, prices for those machines start in the $75K range and go up to probably $200K with all the production features (pallet changers, probing systems, bar feeders, part catchers, etc). Your tooling budget will start in the $10K area, and you’ll need to periodically buy new cutting tools or send out your current tools for sharpening.

      The shop will need all manner of ancillary support equipment – saws, bead blast cabinets, blueing/parkerizing tanks, parts washers. Then you need some computers for CAD/CAM systems. Your CAD/CAM software will probably cost you between $5K and $15K+, with maintenance contracts that run $1K to $2K per package per year.

      You need to be a Type 07 FFL, with a SOT. That’s not much cost overhead. The ITAR licensing of ~$2300/year is.

      You’re probably going to have someone in the shop who has as their job nothing other than handling the paperwork for the silencers, any gun work you have come in, plus the accounting and answering the phones.

      If you’ve started as a one-man shop, and you want to get new designs into production as well as keep cranking out cans for sale, you’ll need to employ at least one machinist.

      You need to make enough off of each product to pay down these machines, plus your overhead (utilities, taxes, rent/mortgage on your facility, wages, payroll taxes, etc). And then you’d like to make a profit in there, somewhere.

      Most CNC shops today don’t take a job for less than $125 to $150/hour. Many with the more capable machines bid at over $200/hour.

      I’ve told you all before that I considered the entry level price for a new, US-made shotgun to be $1K, more for a nice double. You guys don’t believe me. That’s because most of you don’t work in an industry with real costs. You sit at computers, pushing virtual pieces of paper hither and fro. You think that all industries obey Moore’s law. They don’t.

      The costs to make real, tangible goods are high. When I was a farmer, I had $250K wrapped up in equipment, and not one piece of that equipment was new. That’s what it took to merely mow grass & alfalfa, bash it into a brick, get it off the field and put it up in a block. Today, if I wanted to replace that equipment, with the same model and vintage equipment (ie, still not new equipment, just well-maintained used equipment), it would probably cost me $350K. Thanks to stupid emissions BS, older tractors and equipment with diesel engines now have a tidy price premium on them.

      In today’s economy, unless you want to employ lots of people at slave wages, you have to spend big bucks for machines that boost productivity. You could make silencers in the third world, even the monocores, with nothing more than a clapped-out Bridgeport equipped with a DRO, a super-spacer and a lathe, and some cutting tools. You could get the costs way down. And then you’d need to employ an army of machinists, each machinist tied to one machine, making chips doing one operation and passing the part/assembly down the line. That’s how guns used to be made. But if you want repeatable quality and specs… well now your costs start going up again. You’ll need to hire skilled machinists, not some guy from a back alley who will work for a buck an hour.

      • While I appreciate the primer on the microeconomics of the machining industry, we all know this:
        1) We buy plenty items made of machined parts, sometimes much more complicated parts than a suppressor, at a much lower cost than many suppressors on the market.
        2) Suppressors have been around since long before CNC machines existed. Modern manufacturing technology is designed to make the process more economical, not more expensive.

        I suspect suppressors are priced the way they are because of the administrative overhead – The careful record keeping and product storage required to comply with the oppressive regulatory burden involved. This alone prevents more competition in the marketplace. Repeal the NFA and suppressor prices will drop like a rock.

        • The suppressors you’re thinking about 100 years ago used to be made in the sames days when an American-made side-by-side shotgun, with nice, but not extravagant walnut in the stock, color cased receiver and a nice polished & blued barrel cost between $20 to $25.

          Once again, you’re complaints should be directed to the Federal Reserve, and their deliberate policy of setting a target for inflation, which devalues your currency.

        • Because of NFA and all the hassle it brings, today’s suppressors are very nice quality and meant to last forever. You can make cheap .22 L.R. one with stamped sheet metal baffles stacked into thin steel or aluminum pipe. Thread the end cap on it so it’s easy to clean and it doesn’t need cost more than 20 bucks. But the tax stamp is still $200. Who’s going to buy it?

          I made something like that couple decades ago in my teens in Europe for my single shot Suhl 150 .22lr (http://www.gunbroker.com/item/587532006 dang I miss that thing!) out of old bicycle pump. Took me better part of afternoon because I used 1/4″ aluminum for baffles. I had to cut it into squares with a hack saw, drill hole in middle of each square, thread the squares on a bolt and round them in drill press using big file. Then I spaced the flat aluminum baffles with pieces of Al. pipe of slightly smaller OD than my bike pump body ID was.

          With subsonic ammo all I could hear was the striker and than the bullet hitting the target. My father stood 30 yards from me and he didn’t even know I was shooting. It did move my point of impact though.

      • As a single man machine shop that makes my own suppressors, (KMC Silencers), It is great that some one out there understands the costs of machining suppressors. Not many people that sit behind a desk, or simply work for the man understand all that goes into making a simple product. Which a suppressor is not if done right. And that doesn’t include all of the paper-work and licences with the ATF. I make suppressors for the working man. My motto is, if you work, you can afford my suppressor.I really stand by that motto. I make very little if my profit is figured by the hour. Go to my website and look at my prices. kmcsilencers.com and on Facebook. If you think my prices are too high, then by all means don’t buy one. But I would love to sell you one if you so desire.

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