Contents are Copyright 2005 by Robert Silvers and may not be reproduced without permission.
14.5 inch M4 unsuppressed
3D Wavelet Spectrograms
We gathered a collection of 5.56mm silencers and tested them on an M4 (14.5 inch barrel) with Winchester Q3131 ammo. We found that there were distinct performance levels as well as a difference between mounting systems. 10 shots were recorded for each silencer and the peaks of each shot were averaged to come up with the suppressed sound level as well as the net sound reduction. Please note that the readings in the chart are 'linear' and cannot be compared to 'A'-weighted mil-std data. Also note that I discovered that my microphone was clipping at 1 meter for the unsuppressed shots. I had to take the unsuppressed reading at about 2 meters and use the inverse-square calculation to estimate the unsuppressed SPL. What this means to you is that the absolute level of the unsuppressed M4 is possibly off, which in turn means that the net sound reduction might be up to a few dB shifted. The absolute sound levels for the suppressed gun-shots, however, will be unaffected by this -- as well as the relative order of the rankings. And once again, if one silencer is within 2dB or so of another -- consider them equal in terms of sound reduction as you would be hard-pressed to hear a difference even side-by-side although they will likely have tonal differences.
Note that SPG Technologies in Seattle has been using Wavelets for gunshot noise analysis for several years.
Advanced Armament M4-2000
AAC M4-2000 on Colt M4
M4-2000 sound level compared to an unsuppressed M4
The Advanced Armament M4-2000 was the quietest can in this test going by peak sound levels although only by 0.1 dB over the Gemtech M496D -- which is to say -- the results were so close that on a different day either could have been lower. There is some evidence that the Gemtech actually had less energy under the curve but yet must have spiked in some small areas which would record as a 'peak.' If this is true, there is a chance the Gemtech might sound quieter -- but we did not have an opportunity to do listening tests as we were too busy recording numbers. We need to do a shootout of the best cans from this test -- and perhaps enlist some young listeners who still have 100% of their hearing.
I preferred the M4-2000s twist mount over the Gemtech Bi-Lock because there seems to be less to go wrong and it is easier to manipulate when very hot. The Bi-Lock has a coil spring, an o-ring, grease, and other moving parts which might possibly get stuck or need some additional servicing to keep functioning. Ask me how I know. The M4-2000 system just screwed in with 2.5 turns and clicked into place and gets my vote for the single best fast-attach mounting systems for an M4-style rifle.
The M4-2000 was a great looking silencer with excellent performance and can move between other rifles such as the G36, HK33, Steyr AUG, and Sig 552 simply by purchasing flash hiders for those weapons. It has all-welded construction and those baffles should never move.
M4-2000 Mount M4-2000
Advanced Armament SCARS-D
The idea behind the SCARSD was to give FN the shortest practical fast-attach silencer. It might be the coolest looking silencer I have seen on an M4 but we recorded a very significant performance loss of over 8 dB compared to the full size model. The SWR Wolverine and Gemtech M4-96C are also a compact model but without the fast-attach systems and they performed over 4 dB better. Lots of space is used up by the quick-release mechanism which could be used for baffles. While we did not have an AAC Ranger to test, I suspect it would significantly outperform the SCARSD. In the future we need to have a shootout between compact M4 silencers. A 4 dB loss for a compact silencer is a worthwhile tradeoff for many users but 8 dB is asking a lot.
The AWC Optima is not a current model but was included for comparison purposes. It was state of the art in 1988 and helped spawn a trend away from two-point mounting systems although AWC themselves replaced it with a two-point mount with the Optima-2. It performed well and was pleasant to use but was over 30 ounces and was only 0.2 dB quieter than the 21 ounce Wolverine. The Wolverine was also 2.75 inches shorter.
The Gemtech M4-96D is a well tested silencer which essentially tied as the quietest silencer tested in this comparison. It has a fast attach mounting system called the Bi-Lock which allows you to use a special flash suppressor which has two-lugs on it to engage in the silencer and lock after a 90 degrees rotation. One lug on the flash hider is larger than the other to ensure that there is only one way to put it on, which should help maintain a repeatable zero. This can should be on anyone's ultra-short list of what to consider buying.
The M4-96C Predator is a compact thread-mount silencer which scored 4.5 dB louder than the full size M4-96D and had the same sound level as the SWR Wolverine. While it was 0.43 inches longer than the Wolverine, it was 1.8 ounces lighter.
HALO HALO vs M4-96D
The Gemtech HALO can mount onto a standard USGI flash hider by first putting a cap over the flash hider and then screwing the silencer-body into it. It recorded an average of 4.9 dB louder than the M4-96D. This mount doubtless makes sense to certain military users who might not be able to modify their equipment with a custom flash hider.
KAC M4QD KAC M4QD vs M4-96D
The fact that I forgot to take a photo of this silencer just goes to show how much there was to do for this testing. I loved this silencer and I am not sure why. It was the 8th quietest and costs over $1000. There is a 6 month to 1 year wait to buy it, and Knights has the very most difficult ordering process and sales people ever to exist on Earth.
It is a serious-looking can which seems like how military hardware should look. At first I thought the perforated tube was a heat-shield but then I noticed that it has no standoff from the base tube. Apparently this perforated surface is just to reinforce the body which reportedly is made from tubing just 0.035 inches thick. The can sounded good and had a quick-release which worked well although it did have several degrees of rotational play. The baffles appeared to be cast in a star-shaped configuration.
SoundTech M4-Wartech® M4-Wartech Spectrum
SoundTech is a one-man shop by Mark White and has the great feature of that he will make you anything you want. Custom work for SoundTech is almost an everyday occurrence. We have owned this can for a while and was always impressed by its performance but this is the first time we have sound-tested it against the best of the best and see that is is a member of that club. It scored only 1.8 dB louder than the Gemtech which is to say that even side-by-side it would be hard to hear one has being superior. Its dB per ounce ratio was bested only by the Gemtech M4-96C in this test session.
SoundTech Fatboy ®
SoundTech Fatboy® FatBoy Spectrum SoundTech Comparison
The Fatboy had similar performance to the Wartech but had the added advantage of being a little shorter and having less heat gain. The larger diameter, volume, and mass of this silencer should allow it to take more shots on full auto before overheating.
SRT Hurricane SRT Hurricane
The SRT Hurricane was one of the top performing cans in this test and is shorter than the three cans which had slightly better net sound reductions. It has an almost ideal compromise between length and performance and had one of the highest ratios of net-sound reduction to volume. This is an efficient can in the efficiently-class of the Wolverine and Gemtech M4-96C Predator.
SWR Wolverine with AAC Mount
Wolverine with AAC mount Wolverine with AAC cap
Quick-Mount experimental Wolverine vs M4-2000
The SpecWar2 is pictured on SWR's web-page on an m249. You can bet this can is rated for full auto fire. We tested an experimental Wolverine which had an AAC twist-mount -- which is more compact but likely not as quiet as the full size SpecWar2.
SWR Wolverine Wolverine
The Wolverine was a surprise -- a very efficient can that seems to hit the sweet spot between size and performance dead-on. Look in the chart at the dB per ounce and dB per cubic-inch of this can and you can see what I mean. This is a can I might just have to Nord-Lock to one of my short-barrel M16s. I hope to compare this to the AAC Ranger in the future. What a great item for an entry-team who just wants something short to leave on all the time -- always sighted in.
Tactical Innovations Tac16
Tactical Innovations Tac16 Tac16
The Tac16 was cheaper, shorter in length, and quieter in this test than the over-bored XXX Warrior and is fully disassembleable for cleaning. What you see is what you get with this can -- check out the photo. No secrets here.
American Manufacturing XXX Warrior
XXX Warrior compared to M4-96D XXX Warrior
The XXX Warrior we had for testing appeared to be over-bored to also allow for 9mm shooting. This compromise is probably what made it the loudest-testing can in the session. I did not expect this loss of performance and really assumed it would perform almost as well as the high-dollar cans, but for less money. That did not turn out to be the case, which I guess is why this testing was important to me -- because I learned something I did not know before. The manufacturer, American Manufacturing, states that it can handle full-auto fire and has a high-temp ceramic coating. Those sound like nice features so give this a look if you want to do some mag dumps and if you want 9mm capability. While I did not have the chance to test a non-over-bored model, I would expect it to improve the performance. If you want one can to do the work of many, then the over-bore option might be for you.
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