SSS.6.32 - YHM Resonator K and the Savage Model 10 PC .308
/YHM Resonator K on a Savage Model 10 .308 with 20-in Barrel
The Resonator K is designed and manufactured by YHM. It is a 30 caliber centerfire rifle silencer, intended to suppress most cartridges with projectiles appropriately sized to travel through the bore, including 300 Remington Ultra Magnum. It has a 1.56-inch diameter and is 4.8 inches in length without a mount. The silencer possesses 1-3/8”-24tpi rear mount capability and includes the YHM Phantom Q.D. adapter and a muzzle brake or flash hider mount. The included mount adapter results in a silencer system length of 5.65 inches. The user may choose to use third-party mount adapters that interface with the rear mount thread. The silencer is tubeless and constructed of heat-treated 17-4 stainless steel with a a heat treated 718 Inconel blast baffle. The silencer weighs 15.7 ounces with the Phantom Q.D. adapter and brake, as tested. The silencer weighs 9.5 ounces with no mount, as tested. The Resonator K can be obtained from Silencer Shop.
This review contains single-test results using the Resonator K mounted with the Phantom Q.D. Brake on the Savage Model 10 Precision Carbine rifle, chambered in .308WIN with a 20-inch barrel. Federal XM80C 149gr ammunition was used in the test.
Section 6.32.1 contains the results of the Resonator K Test.
Section 6.32.2 contains relative back pressure and Suppression Rating comparisons with selected compact to mid-size .30 rifle silencers.
Section 6.32.3 contains pertinent comparisons of the Resonator K with subsonic 300 BLK and supersonic .308 ammunition.
Section 6.32.4 contains the review summary and subjective PEW Science opinions.
PEW Science Research Note: First Round Pop (FRP) performance of the Resonator K in the supersonic performance regime is characterized in PEW Science Member Research Supplement 6.33 - .30 Hunting Silencer FRP.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80C, the YHM Resonator K mounted with the Phantom Q.D. Brake achieved a Suppression Rating™ of 27.4 in PEW Science testing.
The performance of the Resonator K on subsonic 300 BLK is detailed in previous PEW Science Sound Signature Review 6.30, in which it achieved a Suppression Rating of 40.9.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.32.1 YHM Resonator K Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Resonator K is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. This is a members-only review and includes pressure and impulse waveforms measured at the shooter’s ear. PEW Science thanks you for your support; further testing, research, and development of PEW-SOFT and the Silencer Sound Standard is made possible by members like you!
Table 1. YHM Resonator K Sound Metric Summary
6.32.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories acquired with PEW-SOFT™ are shown below. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz). The peaks, shape, and time phasing (when the peaks occur in relation to absolute time and to each other) of these raw waveforms are the most accurate of any firearm silencer testing publicly available. PEW-SOFT data is acquired by PEW Science independent testing; the industry leader in silencer sound research. For more information, please consult the Silencer Sound Standard.
Figure 1 shows a 1.3 millisecond long portion of the first round sound pressure signature of the Resonator K as measured 1.0 m left of the muzzle. There are four significant waveform features labeled:
The endcap exit event results in an initial overpressure peak magnitude of 144.2 dB.
Secondary jetting reaches a peak of 152.6 dB.
Latent jetting continues with a magnitude of 152.7 dB.
Peak FRP is reached at a maximum of 153.1 dB.
This is a somewhat atypical sequence observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer that exhibits low flow restriction (back pressure); however, internal silencer design can significantly influence the measured timing and pressure amplitudes. Preliminary back pressure comparisons are shown in Section 6.32.2 of this review.
Fig 1. YHM Resonator K First Round Bolt Action Rifle Muzzle Sound Pressure Signature, 24-OCT-2020
For reference, the reader is also encouraged to review the performance data of the Dead Air Sandman-K in Sound Signature Review 6.15. The Resonator K early-time signature differs from that of the Sandman-K in that the jetting is slightly delayed and is of lower amplitude. Other than different baffle geometries and spacing, this flow difference is most likely due to four baffles being present in the Resonator K vs. three baffles in the Sandman-K. The overall, muzzle, and ear Suppression Ratings for the two silencers can be compared directly using the tool in Section 7 of the Silencer Sound Standard - PEW Science Rankings.
Closer views of the first peak of all shots (Fig 2a) and highest peak of the first shot (Fig 2b) are shown below. Figure 2a illustrates the consistency of the coupled bullet end-cap exit and jet event, between all 5 shots during the test. Note the consistency in both amplitude and wave shape which are captured accurately due to the sample rate and raw, unfiltered data stream from PEW-SOFT. Figure 2b shows points later in time during Shot 1 as the maximum sound pressure occurs from the primary combustion event. Note that the total timescale in Figure 2a is 0.2 milliseconds (200 microseconds) and the total timescale in Figure 2b is only 0.1 milliseconds (100 microseconds). PEW-SOFT provides a sampling point every microsecond and the individual data points are shown in Figure 2b to illustrate this.
Fig 2a. YHM Resonator K Bolt Action Rifle Muzzle Sound Pressure Early-Time Peaks, 24-OCT-2020
Fig 2b. YHM Resonator K Bolt Action Rifle Muzzle Sound Pressure Shot 1 Peak, 24-OCT-2020
The primary sound signature pressure histories for all 5 shots with the Resonator K are shown in Figure 3a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 3b, in early time. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 4a. In Figure 4b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2.
Fig 3a. YHM Resonator K Bolt Action Rifle Muzzle Sound Pressure Signature, 24-OCT-2020
Fig 3b. YHM Resonator K Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window, 24-OCT-2020
Figure 4a. YHM Resonator K Bolt Action Rifle Muzzle Sound Impulse Signature, 24-OCT-2020
Figure 4b. YHM Resonator K Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window, 24-OCT-2020
The YHM Resonator K does exhibit perceptible first round pop (FRP). There is FRP in the pressure regime, and it is further evident upon examination of the impulse waveforms in Figure 4 in both rise impulse rise time and slope. PEW Science inner ear modeling indicates FRP will be perceptible to bystanders and to the shooter with the Resonator K on this host weapon platform. Detailed at-ear FRP analyses, along with FRP comparisons with silencers of similar size in the supersonic flow regime are presented in PEW Science Member Research Supplement 6.33 - .30 Hunting Silencer FRP.
PEW Science Note: The rise time to maximum positive-phase impulse measured 1.0 m left of the weapon muzzle is faster than many .30 silencers but slower than that of the Sandman-K; it is postulated that the Resonator K has slightly higher back pressure than the Sandman-K, at least with the tested mount configuration (the Phantom Q.D. adapter and Brake). Detailed quantitative comparisons are provided in Section 6.32.2 of this review.
As typically indicated, first-round sound signatures always differ from subsequent shots, as the atmosphere within the silencer changes. The FRP phenomenon cannot always be shown by viewing only the peak sound pressure. This is one of the reasons why The Silencer Sound Standard requires examining multiple sound signature metrics. Ammunition consistency can play a role in the determination of FRP, however, the close examination of measured pressure and impulse waveforms typically excludes ammunition from the possible factors influencing true FRP, due to the relative consistency of most high quality factory ammunition.
PEW Science has made a concerted effort to characterize the FRP phenomenon with true physiological human inner-ear response analyses. Members may review the data in the latest Research Supplement.
6.32.1.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 5-shot test of the Resonator K suppressor acquired with PEW-SOFT at the shooter’s ear are shown below. Again, the waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz).
The primary sound signature pressure histories at the ear for all 5 shots are shown in Figure 5. The primary sound signature history is shown on the left. A zoomed-in timescale is displayed on the right, in the region of peak sound pressure for Shot 1 and Shot 2. The real sound impulse (momentum transfer potential) histories at the ear from the same 5-shot test are shown in Figure 6. Again, full and short timescales are shown.
Figure 5a. YHM Resonator K Bolt Action Rifle Ear Sound Pressure Signature, 24-OCT-2020
Figure 5b. YHM Resonator K Bolt Action Rifle Ear Sound Pressure Signature, Short Time Window, 24-OCT-2020
Figure 6a. YHM Resonator K Bolt Action Rifle Ear Sound Impulse Signature, 24-OCT-2020
Figure 6b. YHM Resonator K Bolt Action Rifle Ear Sound Impulse Signature, Short Time Window, 24-OCT-2020
When examining the impulse waveforms measured at the shooter’s ear with the Resonator K (Figure 6), it exhibits significant FRP in both the pressure and impulse regimes. Nonetheless, the silencer is quieter than the Sandman-K; both silencers present significant hearing damage risk to the shooter. The magnitude of FRP, relative to subsequent shots, is higher with the Resonator K than with the Sandman-K; this is postulated to be a consequence of the perforated blast baffle of the Resonator K. Research regarding extreme relative FRP magnitudes is ongoing. Despite having a higher relative FRP to subsequent shots, the Resonator K has a quieter first shot to both the shooter and to bystanders than the Sandman-K and may be considered a quieter overall silencer.
6.32.2 Relative Back Pressure and Suppression Rating Comparison (.30 Rifle Silencers)
PEW Science Research Note: As of February 2021, back pressure characterization has undergone refinement and Rev.2 of the Back Pressure Metric has been developed. Research is ongoing. Please see back pressure research updates starting with Sound Signature Review 6.36.
The Resonator K suppressor is intended to be light weight and used for hunting, precision rifle shooting, short barrel rifle use, without significant emphasis on sound suppression performance. PEW Science is currently conducting silencer back pressure research. Figure 7 shows preliminary relative supersonic suppression and back pressure comparisons between selected 7.62mm (30 caliber) rifle silencers shown in public PEW Science Sound Signature Reviews, as of the date of this review publication. The results shown in Figure 7 are calculated from real test data acquired with PEW-SOFT. Please note the following:
The time to reach peak gas momentum transfer potential, as measured 1.0 m left of the weapon muzzle, is the objective quantity used to generate the back pressure data summary.
The waveform characteristics of unsuppressed shots with the same ammunition used in the respective tests are used in the calculations and the unsuppressed relative back pressure and Suppression Rating quantities are shown.
The first shot from each silencer test is omitted from the back pressure computations due to internal gas environment characteristics within the silencer (FRP) that influence peak impulse amplitude, wave-shape, and timing. All unsuppressed shots are included.
Back Pressure Data is normalized to the silencer with the highest back pressure shown, which is the CGS Helios QD with solid endcap from Sound Signature Review 6.13.
Figure 7. Back Pressure And Suppression Rating Comparisons Of .308 Rifle Silencers Using PEW-SOFT Data
The data in the above table is sorted by normalized back pressure metric. From the data, it can be concluded that the YHM Resonator K suppressor may produce slightly lower back pressure than the Dead Air Sandman-S. The reasons for this slightly reduced back pressure are postulated to be due to the silencer’s size (smaller than the Sandman-S) and less baffles than the Sandman-S (4 baffles in the Resonator K versus 5 baffles in the Sandman-S). The postulated 3% lower back pressure of the Resonator K when compared to the Sandman-S is not significant, but it is measurable.
The Resonator K was tested with the YHM Phantom Q.D. adapter and muzzle brake. It is possible that the back pressure behavior of the silencer may change when a different mount system and muzzle device is used. Anecdotal user reports indicate variable back pressure observations with some silencers using different mount systems. PEW Science has not examined the influence of mount system on silencer back pressure.
It is important to note that the back pressure potential of silencers, in general, may not be significant in practical use. For an example of severe performance differential when mount sealing is compromised due to mount design, see the PEW Science data with the Surefire WARCOMP mount and SOCOM762-RC2 in Sound Signature Review 6.26.
It is important to note that back pressure is not the same phenomenon as blow back. Back pressure may cause blow back on a host weapon, or it may not influence host weapon operation when compared to the unsuppressed state; the influence of back pressure characteristics on a silencer’s performance on semi-automatic and automatic hosts may depend on the respective metric magnitudes; this is the subject of future PEW Science research. For example, it is postulated that there is a threshold back pressure metric below which adequate semi-automatic weapon function on typical 5.56x45mm host weapons may be achieved. Whether that threshold is 0.48 in Figure 7 (the Rugged Razor) or 0.39 (the Dead Air Sandman-S), for example, will depend on the particular host weapon configuration. Recent PEW Science research at the time of this review publication indicates that a back pressure metric threshold is probable for gas operated 5.56x45mm small arms. Current research indicates that host weapon component dynamics (AR15 platform bolt carrier, buffer mass, and gas port size) can significantly influence suppressed weapon system performance. Further research is ongoing.
For example, an 11.5-inch AR15 chambered in 5.56x45mm with a mid-length gas system and adequate reciprocating mass (an H3 buffer weight, for example) may be able to be suppressed with any silencer shown in Figure 7 without undue gas blow back noted by the shooter. This type of suppressed small arm weapon system is an example of a gas insensitive host. Conversely, a 14.5-inch AR15 in the same chambering with a carbine-length gas system, relatively large gas port, and standard weight carbine buffer, may produce severe gas blow back noted by the shooter, even with a silencer such as the Surefire SOCOM762 RC2, which is shown in Figure 7 to have a normalized back pressure metric much lower than even some mid-size silencers. This type of suppressed small arm weapon system is an example of a gas sensitive host. On the AR15 platform, silencer gas flow (back pressure) sensitivity is a function of dwell time, inertial resistance, and lock time. Other host weapon types have characteristics that result in more or less gas sensitivity in suppressed operation.
PEW Science note: The relative back pressure percentages described in this section are only valid when examining the data normalized to the CGS Helios QD with solid endcap in Figure 7. PEW Science back pressure research is ongoing. Membership contributions to PEW Science help fund such research.
The YHM Resonator K is slightly quieter than the Rugged Razor and Dead Air Sandman-K to observers. It is also quieter than the Sandman-K to the shooter’s ear, but it is louder than the Rugged Razor at the shooter’s ear. Its back pressure is postulated to be slightly lower than that of the Sandman-S.
6.32.3 YHM Resonator K Subsonic 300 BLK and Supersonic .308 Comparisons
The Resonator K with subsonic 300 BLK on the Q mini FIX bolt action rifle with an 8-inch barrel was previously evaluated by PEW Science in Sound Signature Review 6.30. Below, comparisons of the first shot from that test are shown with the first shot of the supersonic .308 data from this test. This data is shown to illustrate the differences in sound signature between the two weapon platforms, with the same silencer, with the same muzzle device and mounting system.
Figure 8 shows comparisons measured 1.0 m left of the silencer end cap in the pressure regime (left) and impulse regime (right).
Figure 8a. YHM Resonator K Bolt Action Rifle Subsonic 300 BLK and Supersonic .308 Muzzle Sound Pressure Signature Comparison (FRP)
Figure 8b. YHM Resonator K Bolt Action Rifle Subsonic 300 BLK and Supersonic .308 Muzzle Sound Impulse Signature Comparison (FRP)
The higher pressure of the supersonic .308 cartridge results in a significant pressure and impulse magnitude increase. Note the extremely similar waveforms in early time; as soon as the projectile exits the endcap, the gas jetting differences become more pronounced, with the more powerful rifle cartridge overwhelming the positive phase with continued jetting. This is due to both cartridge pressure and gas volume. The Suppression Rating of the silencer on the two platforms differs significantly.
Figure 9, below, compares the waveforms measured near the shooter’s ear. This time, the subsonic 300 BLK waveforms actually exhibit a higher peak pressure than the supersonic .308 waveforms. This is a significant FRP phenomenon.
Figure 9a. YHM Resonator K Bolt Action Rifle Subsonic 300 BLK and Supersonic .308 Ear Sound Pressure Signature Comparison (FRP)
Figure 9b. YHM Resonator K Bolt Action Rifle Subsonic 300 BLK and Supersonic .308 Ear Sound Impulse Signature Comparison (FRP)
The peak transients, while similar in magnitude, do not tell the whole story; the extents of the plot in Figure 9a have been expanded such that the entire waveform history is shown. Note the significantly faster overall decay in amplitude in the subsonic 300 BLK waveform. Even with a higher maximum amplitude, the overall signature is not as intense. This is further illustrated in Figure 9b, where the positive phase impulse at the shooter’s ear is of significantly different shape in early time due to the weapon system variations. Nonetheless, the peak impulse magnitudes are not significantly different during FRP. This shows how severe the first round sound signature can be to the shooter with subsonic 300 BLK, with a small silencer such as the Resonator K. This relation would be difficult to discern when viewing the average peak impulse amplitudes. Close examination of the FRP waveforms are required.
6.32.4 Review Summary: YHM Resonator K on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80C, the YHM Resonator K mounted with the Phantom Q.D. Brake achieved a Suppression Rating™ of 27.4 in PEW Science testing.
PEW Science Subjective Opinion:
As stated in the previous PEW Science test report of the YHM Resonator K with subsonic 300 BLK, it is a very compact, relatively lightweight, and durable .30 rifle silencer. The Resonator K is versatile in that it may be used on many cartridges and with a variety of third-party mount adapters. The user should note that it is a compact silencer and therefore its sound signature suppression performance is lower than that of larger silencers in both the subsonic and supersonic flow regimes.
The Resonator K contains four baffles. The ported Inconel blast baffle is unique among them, as the three primary baffles are an iteration of a curved cone with center “mill-cut” similar to those used by SilencerCo, Rugged, Dead Air, and a variety of other manufacturers. The ported blast baffle in conjunction with the presence of only four total baffles results in a silencer that exhibits relatively high flow rate and significantly less sound signature suppression than larger silencers. It is interesting to note that the Resonator K has one more baffle than the Sandman-K and offers a noticeable sound suppression performance increase.
The included YHM Phantom Q.D. mount adapter and muzzle brake is relatively simple to operate. The mount system is ratcheting and a true “QD” system with coarse threads on the brake (or flash hider) and tooth-engagement notches. The mounts possess a taper interface forward of the coarse threads; a welcome feature to avoid debris build-up in the thread interface. The user may choose to use aforementioned third party mount adapters with the Resonator K. Note that third party mounts may influence the allowable barrel length and cartridge restrictions used with the Resonator K; the user is encouraged to contact the YHM prior to selecting a mounting system for their desired use case. Users have provided anecdotal reports indicating that different mounting solutions may result in different back pressure characteristics of the Resonator K. This phenomenon has not been investigated by PEW Science.
In this review, the Resonator K performance metrics depend upon suppressing a supersonic centerfire rifle cartridge; no easy task. PEW Science encourages the reader to remain vigilant with regard to all supersonic centerfire rifle suppression claims. The gas volume and combustion products created by the firing of the supersonic .308WIN cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact.
The hearing damage potential of supersonic centerfire rifle use is significant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
