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Muzzle Brake Sound Test

Muzzle Brakes: Sound Test

I thought about these muzzle brake tests for over a year before I started this field test. We all know one of the biggest downsides of a muzzle brake is how loud they are. If you’ve shot more than a couple of these, you know some are much louder than others. So I naturally wanted to quantify how loud each model was, but it turns out that is much more complex than it may seem. Steve Adelmann (one of my favorite gun writers) explains the issues involved in quantifying the sound signature of a firearm:

“When you compare decibel measurements from different sources, do so with no more confidence than you’d have of a politician keeping their word. Sound meters suitable for measuring firearm SPLs are expensive and hard to find. Since most of us can’t afford to hire an independent test lab, we’re left with our ears, published figures, and the scant independent studies made available to the public. Unfortunately many available figures result from sound meters designed for OSHA-type workplace measurements, which mischaracterize noise impulses from firearms. Beware the snake-oil salesmen on this point, the suppressor world is full of them, and the game they’re dealing has lethal implications for professionals.” – Steve Aldelmann, Shooting Illustrated

After reading statements like that from multiple sources, and talking to a few people who’d done this kind of sound testing … I was discouraged. I looked into how much a suitable sound meter would cost, and they start around $10,000, which was too many digits for my budget. So, I completely abandoned the idea of a sound test. Ultimately, I’d prefer to not publish anything on a topic, rather than publish something I think might be misleading.

But … one of the guys I called to be part of this test was Zak Smith at Thunder Beast Arms Corp (TBAC). They specialize in precision rifle suppressors, and offer models with Thread-Over-Muzzle-Brake (TOMB) mounts. I’ve always wondered how effective those kinds of muzzle brakes were compared to stand-alone brakes, so I asked if they wanted to include the TBAC 30 Caliber Compact Brake in my field test. After some conversation about all the tests I planned to run, Zak asked if he could bring down his new Ultra series of suppressors to test on my recoil system (view my post on the TBAC Ultra Suppressors). He was interested in gathering some hard data on their recoil reduction, and even plans to create a similar recoil test system to help with future product development. He was so excited about it, he drove several hours to come spend a long day gathering data at my range in Texas.

Of course, since Zak specializes in high-end suppressors … he owns a great sound meter. And now you’re thinking exactly what I was! So I asked Zak to throw in his sound meter when he headed down, and we spent a full morning measuring the sound signatures of all the different models. In return, I bought Zak a steak and measured the recoil reduction of all his new suppressors. But I can’t thank him enough for letting me borrow his nice sound meter, showing me the proper way to set up and run all the equipment, and helping me run through all the muzzle brakes. It’d have been a shame to not include anything on this aspect of muzzle brakes, and without his help … I wouldn’t have. So from me and all my readers: Zak, we really appreciate your help!

The Equipment & Setup

On this test, the equipment was pretty straight-forward. We used a calibrated, military-approved Bruel & Kjaer 2209 Impulse Precision Sound Level Meter equipped with a highly sensitive, precision microphone. This particular model sound meter is described by the American Shooting Journal as the “industry standard” for sound measurement.

Bruel & Kjaer 2209 Impulse Precision Sound Level Meter

We used the same tripods and other equipment that TBAC uses to test their suppressors. There seemed to be a lot of potential gotchas when measuring sound, so I was happy to have an experienced sound technician helping ensure we got it right. I normally encourage readers to run the same kind of field tests I do on their own rifles, but this test is an exception to that. As Steve Aldelmann said, this is a specialized science that requires advanced equipment and meticulous attention to detail. I’m obviously a detailed (borderline OCD) guy, but I couldn’t have done this without the help of a pro.

For these tests, we primarily used a 308 Win with a 20” barrel firing Federal Premium 168gr Sierra MatchKing Gold Medal factory ammo. A 308 Win seems to be what I see people typically use for sound measurements. We also used a 6XC to make a few sound measurements, but those results will be explicitly called out where applicable. These were all the same rifle and ammo combinations as we used in the recoil tests. We recorded the sound level for at least 3 shots with each muzzle brake, and calculated the average for each brake.

SilencerTalk.com offers a great overview of their testing method using the same equipment, along with a disclaimer that is good to keep in mind for my test as well:

While this data is captured in good faith and without bias under controlled circumstances, it is not always comparable to other environments or test equipment. An effort was made to have the data be reproducible and correlate with what a human observer would agree with, but your results may vary. This data must be interpreted with knowledge of how environmental factors such as temperature, humidity, and location effect the results. We do try to compare related products in the same session to make this data as comparable as possible.

All of this data was collected in the same session, and here are the environmental details for the morning we gathered the data: Temperature = 70°, Relative Humidity = 82%, Barometric Pressure = 26.72, Elevation = 3200 ft.

A Brief Primer in Sound

Before I dive into the sound data, let me explain some basics behind the science of sound:

“The decibel (dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly sensitive. Your ears can hear everything from your fingertip brushing lightly over your skin to a loud jet engine. In terms of power, the sound of the jet engine is about 1,000,000,000,000 times more powerful than the smallest audible sound. That’s a big difference!” – HowStuffWorks.com

When it comes to sound, there are two key concepts we need to understand: Sound Intensity and Perceived Loudness.

Sound Intensity (Measured Sound Level)

Because the range of possible sounds is so huge, the decibel scale is different from most. Its logarithmic, which most of us aren’t familiar with. A difference of 10 dB means the sound is 10 times more intense, in terms of acoustic energy. Every 10 dB is an order of magnitude. If there is a 20 dB difference, that means its 100 times more powerful (10×10), and a difference of 30 dB would be 1,000 times more intense (10×10×10)! To help you understand the decibel scale, here are some common sounds along with some visualizations of their relative magnitude (graphic courtesy of  olegvolk.net)

Rifle Silencer Noise Examples

Notice on the chart our baseline is normal speech at 60 dB (1x), then a dishwasher at 63 dB is twice as much (2x), and a vacuum cleaner at 70 dB is ten times as powerful (10x) as normal speech. So a difference of 3 dB can be thought of as twice as intense in terms of acoustic energy, and a difference of 10 dB is ten times as intense.

Perceived Loudness

But, that doesn’t mean 10 dB is 10 times louder. When we switch from talking about sound intensity to perceived loudness, we end up in a strange mix of science and psychology, because loudness is a subjective feeling and can be perceived differently by individuals. For that reason, we actually can’t measure perceived loudness directly. But psychoacousticians have done enough studies to know in general when the sound level increases by 10 dB a sound is perceived as twice as loud (source). Similarly, a 20 dB increase in the sound level is perceived as four times as loud by the normal human ear (2×2).

Clear as mud?! Here is a table showing how changes in measured sound level would apply to both measurements:

Sound Level ChangePerceived LoudnessSound Intensity
+10 dB2x (double)10x
+6 dB1.52x4x
+3 dB1.23x2x (double)
0 db1x1x
-3 dB0.82x0.5x (half)
-6 dB0.66x0.25x
-10 dB0.5x (half)0.1x
-20 dB0.25x0.01x
-30 dB0.13x0.001x

A difference of 1 dB is the just-noticeable difference (JND) for the normal human ear (source), although that may be imperceptible by some people. A difference of 5 dB is clearly noticeable.

Both OSHA and MIL-STD-1474E require hearing protection if sound pressure levels are 140 dB or more (for “impulse” noises like gunfire). However, hearing loss can occur from sounds as low as 85 decibels with long or repeated exposure. Noise-induced hearing loss is cumulative and permanent. Ear protection typically reduces noise by 16-30 dB, which you can find by looking at their Noise Reduction Rating (NRR). For example, the popular Howard Leight ear muffs have an NRR of 22 dB. That may not get you below that 140 mark without “doubling-up” by wearing ear plugs in addition to the muffs. If you’re using a brake, please protect your ears, and pass that message on to your shooting buddies.

The Results

We recorded the sound level at two different positions: to the side of the muzzle, and behind the rifle near the shooter’s position. The sound meter was 1.6 meters above dirt/grass at both positions, in accordance with mil-spec standards.

Sound Test Meter Locations

The B&K 2209 sound meter has a max sound level of 170 dB. So the distances were picked to keep us under that max. Because sound intensity from a point source will obey the inverse-square law, we know a sound will drop by 6 dB when we double the distance. The total sound intensity at the source doesn’t change, but the energy is being spread over a larger area the farther you get from the source. “It’s like spreading a fixed amount of butter on two slices of bread. If one slice is larger than the other, the butter on it will be thinner,” explains NH Crowhurst.

Inverse Square Law

So you can theoretically use the inverse-square law to scale the sound measurements to whatever distance you’re interested in. In fact, there are calculators designed to do just that. For example, mil-spec testing is typically done 1 meter to the side of the muzzle, but our sound meter was 1.524 meters to the side of the muzzle (to keep from pegging the 170 dB max). We measured the sound level of a bare muzzle to be 163 dB at 1.524 meters, so the inverse-square law predicts that to be a sound level of 167 dB at 1 meter … which is precisely what we measured for 3 bare muzzle shots we fired at that distance.

Without further ado, here is the data we recorded to the side of the 308 Win:

Average Muzzle Brake Sound Level To The Side of 308 Win

We also did a few measurements with the 6XC with a 24” barrel. For that rifle, we found the average sound level with a bare muzzle to be 163.4 dB, which is less than 1 dB difference from the 308 and therefore not a perceptible difference to the human ear. I also measured the Tubb Precision Muzzle Brake to the side of the 6XC, and it metered at 165.7 dB, which is 2.3 dB more intense than the bare muzzle.

Honestly, I had a case-head separation in my 6XC that knocked it out of commissioned for the rest of the day. So unfortunately, since I only had access to the sound meter that one day, I wasn’t able to meter the JEC Customs Recoil Reduction Muzzle Brake. I also wasn’t able to meter the Tubb Precision Muzzle Brake from behind the rifle. Sorry, guys!

Most sound measurements are taken from the side of the rifle, in accordance with the military specifications. But I also measured the sound levels from behind the rifle, closer to the shooter’s position. That is far more interesting to me, and seems more applicable for judging how loud a muzzle brake is. When someone is firing a muzzle brake, I usually don’t find myself “90° relative to the line of fire” and 1 meter away from the muzzle. Even if I did … I certainly wouldn’t still be there when they fired the second shot. 😉

Here are the average sound levels we metered behind the rifle, near the shooter’s position:

Average Muzzle Brake Sound Level Behind Rifle

What’s interesting here, is the order of the muzzle brakes is much different than it was to the side of the muzzle. A big reason for that is because some of these brakes have angled baffles that direct more of the blast rearward. So when you meter those brakes from the side, you aren’t picking up all the pressure being sent back toward the shooter. But, when we metered the sound level from the second location, we come closer to capturing the effect a shooter or spotter would feel behind the rifle. That resulted in almost all the brakes with angled baffles metering louder than those with straight baffles.

When we measured the sound level from the side, there was only a difference of less than 2 dB from the quietest brake to the loudest. But from behind the rifle, that range jumped to 9 dB! That means from behind the rifle, there were some brakes that sounded about twice as loud as other muzzle brakes.

Now, remember that I didn’t have a chance to measure the 6mm brakes from behind the rifle, but when I metered the Tubb Precision Muzzle Brake from the side, it was almost identical to another 4-port brake with a 90° baffle design, the CSR Blast Tamer Muzzle Brake. So the Tubb brake may be similar to the Blast Tamer behind the rifle as well. Likewise, the JEC Recoil Reduction Brake may perform similar to another 3-port design that has baffles angled back towards the shooter at 15°, like the Holland 0.985” Radial Quick Discharge Muzzle Brake. That would actually put both of those brakes side-by-side at around 161 dB. That is just my rough estimates of where those brakes may have ended up based on the designs. Ultimately, I wish I could have metered them, but unfortunately, I only had access to the sound meter that one day and wasn’t able to get it done.

As I mentioned earlier, most of us aren’t used to working with logarithmic scales, and we may not realize how big of a difference there is between these numbers. So I translated those measured sound levels to the difference in perceived loudness compared to a bare muzzle, using a calculator intended for that purpose. The chart below shows how much louder each brake was compared to the bare muzzle.

How Much Louder Is A Muzzle Brake

If we just start at the top, you can see the OPS muzzle brake was the “quietest” of the batch. It says “+ 41%”, which means it’s still 41% louder than the same rifle without a brake (i.e. 1.41 times as loud). If you’ll remember, the OPS brake was also the worst performer when it came to recoil reduction … so I’m glad to see it wasn’t both ineffective and loud. 😉

Most brakes hovered around 100%, which means they sound twice as loud as the rifle with a bare muzzle.

Finally, we have some brakes that were more than twice as loud. We see some familiar names at the bottom of this chart: APA Fat B* and Little B* Brakes, the Alamo Four Star Muzzle Brake, the Holland Radial Quick Discharge Muzzle Brake, and the Impact Precision Muzzle Brake. If you’ll remember, those were some of the best performers when it came to recoil reduction.

There seems to be a correlation between how loud a brake is, and how well it reduces recoil. Most “quieter” brakes aren’t good at reducing recoil, and most of the brakes that are great at reducing recoil are very loud.

Like the other tests, I assigned a rating to each of the brakes in terms of how loud they were. My rating system worked like this: If a brake was only 20% louder than a bare muzzle, it would receive a full 10 rating. If a brake was 150% louder than the bare muzzle (which would be 2.5 times as loud), it would receive a rating of 0. The ratings were based on the measurements we made from behind the rifle.

Here are the loudness ratings, and I included the recoil reduction ratings for each brake as well in a semi-transparent color to show the side-by-side comparison.

Muzzle Brake Loudness Rating vs Recoil Reduction Rating

The brakes are ordered by their loudness rating, but you can see most of the low recoil reduction ratings are towards the top and most of the high ones are towards the bottom. That is that correlation I was alluding to earlier. But you can also see that the order isn’t perfect, so there are some brakes that provide more recoil reduction compared to the increased loudness you have to endure … and there are some that go the other way (they’re unusually loud and don’t reduce recoil much).

A few noteworthy performers are the Badger Ordnance FTE Muzzle Brake and Seekins Precision ATC Muzzle Brake, which weren’t as loud as most of the brakes and they provided decent recoil reduction as well. Both the JP Recoil Eliminator and JP Compensator muzzle brakes also seemed to have good recoil reduction compared to how loud they are from the shooter’s position. The Center Shot Rifles Blast Tamer and Holland Radial Quick Discharge Muzzle Brake were good at recoil reduction, and not the worse in terms of loudness. And finally, the Alamo Four Star Cowl Induction Brake was one of the top performers in terms of recoil reduction, and it actually didn’t end up being the loudest.

Some of these brakes are clearly louder than others, but make no mistake … they’re all very loud. Here’s my analogy: If you got hit by a vehicle at 70 mph, it is going to hurt … regardless of whether it was a compact Kia or a big truck. Neither would be pleasant! Likewise, none of these brakes are pleasant. I’ve seen guys online looking for the “quietest muzzle brake,” and that is like looking for the tallest Leprechaun. You’ll likely be disappointed at the end of your hunt.

How Suppressors Compare

I’ve shown how suppressors compare in the recoil test and the ability to stay on target, so it’s only fair to show how they compare here. We all knew it would be a huge difference, but brace yourself. It’s a huge margin.

Suppressor vs Muzzle Brake

I tested all 3 of the new Ultra series of suppressors from Thunder Beast Arms Corp (TBAC), and they were all stellar at reducing sound. The Ultra 9 is their 9” suppressor, Ultra 7 is the 7”, and the Ultra 5 is the 5” model.

You can see there is a 43 dB difference from the quietest suppressor to the loudest muzzle brake. To the human ear that would likely sound 16 times quieter! Remember, psychoacousticians tell us 10 dB is usually perceived to the human ear as twice as loud. So a difference of 40 is 4 sets of 10, which is 4 doublings … 2×2×2×2 = 16.

If noise level is one of the big things you’re concerned about, the suppressor is clearly the way to go. If you’re trying to balance recoil reduction, ability to stay on target, noise level, and muzzle blast … you found the right field test! I’ll look at muzzle blast next … so stay tuned!

Want to be the first to know when the next set of results is posted? Sign-up to receive new posts via email.

Other Post in this Series

This is just one of a whole series of posts related to this muzzle brake field test. Here are links to the others:

  1. Field Test Overview & Line-Up: Overview of how the tests, what brakes were included, and which were caliber-specific.
  2. Recoil Reduction Results: Let’s get right to the meat!
    1. Recoil Primer, Test Equipment & Rifles: Explains how I tested, and what equipment and rifles were used.
    2. Results for 6XC and 6.5 Creedmoor: Recoil results for the mid-sized 6mm and 6.5mm rifles.
    3. Results for 308 Win and 300 Norma Mag: Recoil results for the mid-sized 30 caliber and large magnum 300 rifles.
    4. Summary: Overview of recoil results from all rifles, and overall ratings of each muzzle brake.
  3. Ability to Stay on Target: Lasers and high-speed cameras were used to objectively quantify how well each muzzle brake helps you stay on target through a shot.
  4. Sound Test: A high-end sound meter was used to measure how loud each brake was to the side of the rifle and at the shooter’s position behind the rifle.
  5. Muzzle Blast & Ground Signature: High-speed videos were shot of each brake to show the direction of the muzzle blast, and the impact that could have on the shooter.
  6. Overall Summary: Putting all the results together in a summary that is easy to take in, and do side-by-side comparison, allowing you to draw your own conclusions on what muzzle brake is best for your situation.

About Cal

Cal Zant is the shooter/author behind PrecisionRifleBlog.com. Cal is a life-long learner, and loves to help others get into this sport he's so passionate about. Cal has an engineering background, unique data-driven approach, and the ability to present technical information in an unbiased and straight-forward fashion. For more info, check out PrecisionRifleBlog.com/About.

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50 comments

  1. Printed out to absorb at breakfast in the morning…..thanks for what ya do Cal.

    • You bet, buddy! There seems to be a gaping black hole in the intranets for data like this, so I’m glad I was able to finally get it all published.

      Thanks,
      Cal

  2. Cal,

    Do you think it would be possible to create a graph that includes loudness rating (0-10), recoil reduction rating (0-10), and rating for ability to stay on target (0-10)? Maybe call the last one follow-up rating or gun jump rating or something. David Tubb says it was a very important consideration.

    I added up all of the ratings for loudness and recoil reduction and found it a bit humorous that the Four Star was near the top even though it basically punted on the loudness aspect.

    • Absolutely, Chad! In fact, I’ll do even better than that. I’ll include all those things, plus stuff like rating for muzzle blast, and also a rating for all the little things like whether you have to pay for it to be gunsmithed or can just order it and screw it on. I plan to do all that in the summary post, which should be very soon. The remaining posts should fly by compared to the others. They are far less technical, and MUCH easier to write. Posts like this one and the recoil posts take me forever to write, because I try to make super-technical topics approachable by just about anyone. You’d laugh if you knew how much time I spent on this post and the recoil primer post, but I hope they laid a foundation that some shooters didn’t have. Educated consumers are powerful.

      So stay tuned! I hope to have that to you in the near future.

      Thanks,
      Cal

  3. Why did I think Muzzle Brakes would quiet down my rifle? Boy was I surprised …

  4. Cal

    Great article. I will also have to print it out and digest it over several days (or maybe a little longer). Thank you for the integrity of your approach.

    • You bet! That’s one of the highest compliments anyone has ever paid me. Integrity is critically important to me. I’m a big quote guy, so I can’t resist sharing two:

      “If you have integrity, nothing else matters. If you don’t have integrity, nothing else matters.”

      “Integrity without knowledge is weak and useless, and knowledge without integrity is dangerous and dreadful.”

      I try to keep those things in mind and live them out. So the fact that you noticed that is really encouraging!

      Thanks,
      Cal

  5. Excellent article! Thank you. I was just thinking about the omega suppressor with the brake (to help stay on target) in front of the suppressor. That would add sound and counteract the suppressors quietness,to some unknown degree. I’m debating which suppressor to buy, omega or the ultra 9. Hmm…

    • I hear you! Me too. I wonder how much it helps you stay on target. After looking at it more, it seems like it sends air equally in all directions … so I’m concerned it may not help stay on target as much as reduce recoil. SilencerCo’s marketing says that feature is for reduced recoil, and doesn’t mention anything about staying on target. If they’d just make it somewhat directional, it’d help … but then you’d need to time it with that barrel (or do something more complex in the mount). But I’m with you! I wonder what the quantified benefits and drawbacks are of that design … maybe one day I’ll test it. I’ve definitely thought about it a lot through this whole process.

      Thanks,
      Cal

  6. Great report very useful information.

  7. Cal,
    I’m new to the PRS world and am so glad that your tests are available. In our shooting group (FL) some of us think that you can walk on water (I believe you can) :). Seriously, we can not thank you enough for all your attention to details, explanations, good & bad with each item tested and most important just being you. Obviously this takes a lot of planning, time & money. Passion is funny thing. When we love something we seem not to work hard or feel like we are not working hard at it. So I just wanted to thank you and say ‘Son, you found your calling please keep at it’. I’ve never been to TX ( I hear it’s a BIG state) so when I do I would love to visit your range and perhaps go shooting together. Thank you Cal again.

    • You’re too kind, MP. I’m nothing special. Just an average shooter, but I do feel strangely equipped for this kind of thing. Its a unique combination of a few characteristics like my analytical/engineering/OCD nature, plus resourcefulness/pragmatism, hunger to learn, enjoyment of writing/teaching/technology, and heart to help others. And of course I can’t deny my deep passion for the art and craft of the precision rifle. It definitely doesn’t feel like work to me. But then again, my full time job (in another industry) doesn’t feel like work either. I’d do it for free, if I didn’t need the money! I love what I get to do every day, regardless of whether that is a week day or a weekend. I get to have a lot of fun, love the people I get to work with, learn every day, and have a deep sense of purpose.

      As I mentioned in another comment, I’m a big quote guy, and I can’t resist sharing one more: “The master in the art of living makes little distinction between his work and his play, his labor and his leisure, his mind and his body, his education and his recreation, his love and his religion. He hardly knows which is which. He simply pursues his vision of excellence at whatever he does, leaving others to decide whether he is working or playing. To him he is always doing both.”

      When I first read that, I thought it finally articulated what I feel. I’m blessed to be able to do this stuff. It is hard, and does take planning, time, and money … but it’s fun too. Once again, I appreciate the kind words.

      Thanks,
      Cal

  8. Cal

    Thanks once again for the thorough analysis. Being new to the sport (and having a TBAC Ultra-7 on order), I’m now wondering what is the value of suppressors for overall performance (in terms of recoil reduction and staying on target)? Other than suppressors strengths at reducing sound and looking cool, it appears there are a number of muzzle brakes that outperform suppressors.

    • I think your correct, Jeff. At least that is what I’m learning through this whole process. It seems like there are a few things suppressors do better than most brakes: Reduce noise (near the point where you don’t need hearing protection), reducing the pressure shockwave at the shooters position (especially important if you’re in an enclosed place or shooting next to others), and have that exotic, James Bond cool factor. But from a practical, getting-rounds-on-target perspective, muzzle brakes offer a lot of value. You can now understand why more of the top PRS shooters in the nation use muzzle brakes over suppressors. It’s been interesting quantifying all this stuff. I’m learning right along with you.

      Thanks,
      Cal

  9. Just want to thank you for sharing the great info. It is very useful and cuts through a lot of B.S.

  10. So did you quantify the difference in recoil/sound between the Ultra 7 and the Ultra 9 enough to decide which you want? 🙂

    • Well, it’s not an easy decision, but for my use I think the Ultra 7 is the winner. It’s a little lighter and a little shorter, but the sound suppression and recoil reduction isn’t a lot different than the Ultra 9. Now the 5″ model loses a lot, but there isn’t a huge difference from 7 to 9. I wish it helped you stay on target more, and wish it had better recoil reduction … but it is what it is. I’m not sure there is a better suppressor out there. I’ll probably still use brakes in competitions.

      Which one are you going for?

      Thanks,
      Cal

      • I’m not sure. I’d need to see some tests on the difference in recoil between the 7 and 9… sound is rather more subjective, but I’ll trust that you decided it wasn’t that perceptable. 🙂 Any thoughts on doing 5 vs 7 vs 9 in recoil?

        Thank you,

        Sarah

      • The difference in recoil between the Ultra 7 and 9 is roughly the same difference between those in terms of sound. There is a difference, but it’s not astronomical. Based on my measurements, the Ultra 9″ is about 10% better at reducing recoil than the Ultra 7″. That is true for peak force, overall impulse, and combined average for the 308 I tested. The combined average recoil reduction for the Ultra 7 was 16%, and the Ultra 9 was 27%. I’ll likely publish more details about those and the other suppressors I tested in a future post.

        Hopefully that gives you a little more to go on. There isn’t a “right” choice here. To me, if I’m primarily concerned with performance, I’m going muzzle brake. If I’m primarily concerned for comfort for me and other shooters around me, I’m going suppressor. The 7″ or 9″ really comes down to striking the balance between maneuverability/weight and recoil/sound. The sound suppression on both are “good enough” for me (totally a personal opinion though). Based on my testing, they both get you below the 140 dB mark behind the rifle. So, once again … there isn’t a “right” choice. It all depends on your personal preferences and the specific application.

        Thanks for the questions! I bet others were wondering the same thing.
        Cal

  11. It’s a bit tight in my mind as well! 🙂 I’d really have to see the difference in recoil between the 7″ and 9″, but haven’t found data on it yet. Shorter length is huge for me, though, but the >50% less noise isn’t bad either… rather torn on it all.

    • Thank you very much for those recoil reduction numbers. 🙂 It’s exactly what I was looking for!

      That means those extra two inches do as much as 4.8″ (27-16=11% on 2″, compared to 16% on 7″). Huge efficiency bonus for that little extra length and weight. 🙂 Pretty much has me decided on the Ultra 9!

      Thank you,

      Sarah

  12. Superb job. This series with it’s hard-won data clarifies some aspects and raises quite a few new questions. For example about basic design choices and market niches.

    Maybe there are enough buyers for a slightly modified APA-type muzzle brake with a blast deflection device in form of tube around it. Maybe it gives up something in recoil reduction but could greatly reduce the sound increase behind the gun and less so beside it.

    Or why don’t we have suppressor which might trade some noise reduction for a more directional design engineered to stay considerably better on target? Maybe a shorter suppressor with a larger diameter or a wide box and fewer, more aggressive ‘baffles’ could be the way to go for some target shooters or some military applications, who knows?

    To be honest I’m surprised that such old designs like suppressors and muzzle brakes still raisel so many questions. Thankfully your precious data gives as a bit firmer ground to speculate on and for further tests. Actually the many questionmarks behind current designs and potential solutions are perhaps the greatest praise for your efforts or good scientific work in general.

    • Great questions! I’m with you. I’ve thought some of the same things through this study. Maybe there is a market for something between a muzzle brake and suppressor. Could there be a slightly louder suppressor that gives you some of the additional benefits of a muzzle brake, like staying on target or better recoil reduction? Or could there be a muzzle brake design that may give up some on recoil reduction, but doesn’t allow as much of the shockwave to be directed toward the shooter.

      That’s the thing about learning! The more you know, the more you realize how much you don’t know. The real art is learning to continually ask questions. “The sign of intelligence is that you are constantly wondering. Idiots are always dead sure about every damn thing they are doing in their life.” – Vasudev

      I know others have done this kind of testing, I just haven’t seen much published on it … at least not where it was publicly accessible and presented in a way most people could take it in. Ultimately, I hope this study sparks a lot of conversations and questions, like the ones you’ve mentioned. Who knows, maybe new products will become available in the not so distant future. If that happens, we all win.

      Thanks,
      Cal

      • Cal,

        Great work as usual. It was my pleasure to come down and meet you for part of this project.

        One aspect I’d love to see thoroughly investigated are the factors that influence a shooter’s ability to “shoot well”. For example, ability to shoot accurately over a shooting session (day). Another question I’d love to see explored is how people perceive recoil, IE, a perceptual recoil model.

      • Those are great points, and I’d like to see some hard data on that stuff as well. I went to the grand opening of a shooting complex a few weeks ago, and there were a ton of vendors there for the event. The guys from Surgeon brought a few rifles, including a 50 cal … and having never shot one, I thought I’d try it out. The recoil on it wasn’t near as bad as I expected. It honestly was comparable to a lot of large magnum rifles, at least on the rifle/chassis I experienced. But it had a huge brake on it, and the muzzle blast was stupid. The Surgeon rep said that most people can take the recoil all day, but nobody is immune to that pressure shockwave from the blast. He said you’d definitely have to quit shooting because of that before the recoil. I never had thought about that before he mentioned.

        I read a thick stack of whitepapers and studies related to recoil before I started this test, and I do remember one the military did that is somewhat related to what you’re referring to. It was a study the US Army did in 2004. Here is a link to it:

        Shoulder-fired weapons and high recoil energy: Quantifying injury and shooting performance

        Now that doesn’t speak to how blast or noise level affects shooting performance, but your comments just made me think of this study. It’d be interesting if there was a similar study done for muzzle blast and noise levels, and how those related to sustained accuracy. If anyone knows of a study like that which has already been done, please chime in.

        Thanks,
        Cal

      • ” Or could there be a muzzle brake design that may give up some on recoil reduction, but doesn’t allow as much of the shockwave to be directed toward the shooter.”
        —-

        Check out linear compensators such as the Levang. I would have loved to see some of these included.

  13. Awesome work! I’ll have to read this and the other brake test articles again to digest fully, but so far, these are great! Fantastic that you were able to get ahold of the sound equipment; such an important factor that is rarely, if ever, studied for those concerned with sound.

    • Thanks, Phil. I agree that there doesn’t seem to be a lot of data out there on this topic, especially from independent sources. I’m glad Zak was willing to help out. I’m usually very resourceful on stuff like this, but I couldn’t have done it without him. It’s an important topic. It reminds me of something Chris Kyle mentioned in his book related to his 338 that had a muzzle brake:

      I used a .338 [Lapua Mag] on my last deployment. I would have used it more if I’d had it. The only drawback for me was my model’s lack of a suppressor. When you’re shooting inside a building, the concussion is strong enough that it’s a pain – literally. My ears would hurt after a few shots.

      And most veteran shooters can’t hear! Virtually all of us have significant permanent hearing loss. Education might help people realize how important it is to protect your ears. I’d bet most people don’t realize that you need to double-up on hearing protection with most muzzle brakes to get under 140 dB, so I hope this brings awareness to stuff like that as well. Thanks for the feedback!

      Thanks,
      Cal

      • Yeah, I’m not qualified to speak to what our military experiences, but even our local gun range necessitates doubling up on hearing pro in a couple areas due to concrete barriers. I do know we need to take care of our service men and women; if it’s not already, electronic hearing aid-type ear pro (e.g. Walker’s Game Ear) should be standard issue.

  14. Thanks Cal for the more than thorough analysis. Do you have the individual db reading for the 9, 7, and 5 ultra? I’d like to know what it will levels out at after the first round pop. Is there more testing in the pipeline for suppressors in general?
    Thanks again,
    Blake

    • Hey, Blake. I did run through sound tests with those, and the results matched what I published on those suppressors back in February. I don’t have a lot more data than that to publish right now. I may end up doing a suppressor test in the future, but the regulations around those will make that difficult. I have no plans to start that any time soon, but it’s definitely an idea I have for a future field test.

      Thanks,
      Cal

  15. There are two muzzle brakes who claim to be quiet

    The Gentry Quiet Brake

    http://gentrycustom.com/products/

    and the Vias brake.

    I would be very interested to see how effective these are recoil reduction and how much quieter they are, if any, compared to normal muzzle brakes.

    • Doug, I’d bet they weren’t any quieter than the ones tested here. The Vias brake is similar to the Shrewd and Seekins Precision. The Gentry is very similar to the Shrewd. I did try to contact Vias to see if they would like to be part of this, and they would never respond to my multiple emails or phone calls. They weren’t the only company that was unresponsive. I feel like if you don’t want to be part of something like this, it says something about your confidence in the product. I loved JP’s response. They were reasonably concerned that it was a fair test, but after I satisfied that … they were all about it. They had an attitude of letting the chips fall where they may, and hopefully they’d learn something. They were confident in their product. I had the feeling that they already knew how it compared to most of the competition. They have a reputation of being a company that tests it’s products more thoroughly than most, so that may be true. I feel like that is the healthy reaction to this kind of thing … not ignoring phone calls and emails. Those are very different reactions, and I think you can draw a few conclusions from that about how the company is ran.

      I did find a significant correlation between sound level and recoil reduction. While I didn’t calculate a p-value … it seems pretty apparent and convincing to me.

      I will say the Seekins Precision has holes drilled longitudinally (like the Vias), and I’ve heard the idea there is those may cause the gases to swirl and disrupt/soften the shockwave that comes back at the shooter. The Seekins brake was one of the quieter brakes relative to it’s recoil reduction … but it was not “quiet”.

      Here are my thoughts on finding a “quiet” muzzle brake:

      Some of these brakes are clearly louder than others, but make no mistake … they’re all very loud. Here’s my analogy: If you got hit by a vehicle at 70 mph, it is going to hurt … regardless of whether it was a compact Kia or a big truck. Neither would be pleasant! Likewise, none of these brakes are pleasant. I’ve seen guys online looking for the “quietest muzzle brake,” and that is like looking for the tallest Leprechaun. You’ll likely be disappointed at the end of your hunt.

      The Vias or the Gentry “Quiet” Brake may be the tallest Leprechaun, but even if they are … I bet they’re still pretty short. And both of those are unidirectional brakes and will have a terrible ground signature, just like the Shrewd. For many precision shooters, that is a deal-breaker.

      Thanks,
      Cal

  16. Hi,

    Great article and thanks for it! For me, I did try the VAIS a few years back after research and their claim of being the quietest brake. On my Ruger Laminate Compact .308 with a 16.5″ barrel. I can tell you it made a huge difference in recoil and the sound level didn’t seem to go up as much as other brakes. Since they make the claim it would be nice if you could somehow manage to find some way to include them in this. Thanks again, appreciate the great review!

    • Hey, JT. I hear your point, but I reached out to VAIS multiple times to see if they wanted to be part of this, and they didn’t return my phone calls or emails. That’s just not the right way to treat people, regardless of whether they were interested in being part of this test or not. At least give me a call back. Honestly, I don’t want to deal with companies like that, so it’s unlikely I’ll ever test their product. If any of the PRS pros were using a VAIS brake, it might be different … but they aren’t (see the data). So I’m afraid you’ll have to convince someone else to test that brake. I’m out on VAIS.

      Thanks,
      Cal

  17. Ok, since nobody has NO muzzle device, it would have really helped to have the A2 birdcage as the baseline. Can you tell me how many DB the A2 is in this test?

    • I did test a TBAC Flash Hider, which is similar. From the shooter’s position it was 148 DB. Yes, I realize that is 2 DB under the bare muzzle. What we thought is the flash hider works by disturbing the pressure wave and swirling gases, which could result in the decreased the sound pressure. It’s just a theory though. Interesting data though. We measured it multiple times, and I’m confident in it.

      Thanks,
      Cal

  18. Cal,

    This was a fantastic article. I appreciate the explanation of data, experimental setup, and analysis.

    Did you happen to look at any other sound characteristics (e.g., duration, peak frequency, etc)? I would be really interested to see that data. Is there any way you could share some of the raw data?

    • Joe, the only thing I recorded was the max reading. I would have liked to gather the full signature, but I’m not sure what kind of equipment would have been necessary to do that. I believe the system we used cost $10,000+, so I’d be scared to hear what that other system would cost. Through this test, I learned sound equipment can be ridiculously expensive! Sorry I couldn’t be more help.

      Thanks,
      Cal

  19. Call
    Ive seen so many post thanking you for your time and willingness to share with you fellow students. I can’t fathom how much time you put it all your research!
    I’m new into precision rifles. My first long distance rifle is a Remington 700 223 vsf with a 1/12 twist. I quickly found out what it would do when we were trying to zero with 77gr match 🙁 I’m now…looking at actions, barrels, and chassis. I think the only thing I got right before was my scope. I’m going with a MPA chassis, and gonna try a Criterion barrels on a old Remington 700 that I had. I’m hoping to save all the gunsmith charges and change the barrel myself. I will used more of your info on other choices like breaks, and a suppressor.
    Again…thank you thank you
    Richard

    • You bet, Richard. It’s easy to get overwhelmed with this stuff when you’re first starting out, so I’m glad I could help.

      Thanks,
      Cal

  20. Hi Cal I just bought a mossberg MVP varmint 5.56 and I what to make it more accurate.From what I have seen it is all over the bord about 2 inches or more. I was thinking of a muzzle brake would help but I don’t want to make it louder and it is already threaded for one. Thanks James

    • James, I’m afraid a muzzle brake won’t have a significant impact on precision (i.e. tightness of groups), if any. Some claim that “transitional ballistics” will be smoother with a muzzle brake, which is a short period between when the bullet leaves the barrel and when the pressure behind the bullet stabilizes. But, that won’t make a 2″ gun a 1″ gun. There are a lot of other factors a gunsmith would need to correct to make a difference that big, although handloading can sometimes help you “tune” a factory rifle and improve precision in a measurable way. Honestly, the cheapest answer might be to start with a different rifle. I realize that’s not what you’re hoping to hear, but if I were in your shoes … it’s what I’d need to hear. Depending on your budget, a Ruger Precision Rifle would be a great option, or if your budget is tighter I usually recommend a Savage rifle. The heavier the barrel profile, the better.

      Thanks,
      Cal

  21. Hi Cal, Great read. I happen to work for the company that makes the Sound Level Meter in the story. If you ever need support making these measurements, I might be able to help you out. I’ve come out and done this type of measurement for a few of the major silencer manufacturers. Send me an email and we can discuss.

    • Wow, that’s awesome, Jack! Thanks for chiming in. I was certainly glad I had a veteran with me when I tested all this stuff, because even as an engineer … I underestimated how complex the science of sound is! There seem to be a lot of pitfalls or unintended consequences related to the equipment and setup that can skew the results. I assume that is why you have traveled to help manufacturers with this kind of testing. I certainly value your expertise, and appreciate the offer to help. If I ever do a test like this again (and I’ve thought about doing it for suppressors), I’ll be in touch.

      Thanks,
      Cal