SSS.6.105 - Thunder Beast Dominus-SR and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle (Free Version)
/Thunder Beast Dominus-SR on the MK18 5.56x45mm AR15 with 10.3-in Barrel
The Dominus-SR is designed and manufactured by Thunder Beast Arms Corporation (TBAC). 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 is also intended to be a hard-use silencer for the 5.56x45mm cartridge. The Dominus-SR has a 1.8-inch primary diameter and is 6.9 inches in length with its locking collar in the “locked” position; this proprietary mounting system interfaces with various SR series brake mounts from TBAC, intended to adapt the system to a variety of host weapon barrel thread specifications. The silencer is constructed entirely of titanium, and the SR series mounts are machined from heat-treated 17-4 stainless steel. The silencer weighs 12.5 ounces and the 1/2-28 tpi SR brake mount weighs 5.2 ounces, for a total system weight of 17.7 ounces, as tested. The Dominus-SR may be obtained from Silencer Shop.
This Sound Signature Review contains single-test results using the Thunder Beast Dominus-SR with the SR brake mount on the MK18 Automatic AR15 rifle, chambered in 5.56x45mm NATO with a 10.3-inch barrel. Federal XM193 55gr ammunition was used in the test. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.
Section 6.105.1 contains the Dominus-SR test results and analysis.
Section 6.105.2 contains a detailed holistic signature comparison case study, featuring the Thunder Beast Dominus-SR and the Surefire SOCOM556-RC2 on the MK18 weapon system (Members Only).
Section 6.105.3 contains Suppression Rating comparisons of the Dominus-SR with dedicated 223 and 30 caliber silencers on the current market, including the KAC 5.56 QDC, CGS SCI-SIX, Dead Air Nomad-30, YHM Turbo T2, Dead Air Sandman-S, HUXWRX FLOW 556k, Energetic Armament ARX, KAC QDSS-NT4, Rugged Razor556, Otter Creek Labs Polonium and Polonium-K, Surefire SOCOM556-RC2, HUXWRX HX-QD 556 and HX-QD 556k, Q Trash Panda, CGS Helios QD, SilencerCo Saker 556, Rugged Razor762, and others.
Section 6.105.4 contains the review summary and PEW Science subjective opinions.
Summary: When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the Thunder Beast Dominus-SR mounted with the SR brake mount achieved a composite Suppression Rating™ of 26.0 in PEW Science testing. As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.105.1 Thunder Beast Dominus-SR Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Dominus-SR tested with the SR brake mount is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. The data acquired 0.15 m (6 in) right of the shooter’s ear is only available to membership supporters of PEW Science and the Silencer Sound Standard. You can support PEW Science testing, research, and development with a membership, here. State-of-the-art firearm sound signature testing and research conducted by PEW Science is supported by readers like you.
Table 1. Thunder Beast Dominus-SR Sound Metric Summary
6.105.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories from a 6-shot test acquired with PEW-SOFT™ are shown below. Six cartridges were loaded into the magazine, the fire control group positioned to single-shot, and the weapon was fired until the magazine was empty and the bolt locked back on the follower of the empty magazine. Only five shots are considered in the analysis. The signatures of Shot 6 are displayed in the data presentation but are not included in the analysis to maintain consistency with the overall PEW Science dataset and bolt-closing signatures. 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.
The primary sound signature pressure histories for all 6 shots with the Dominus-SR are shown in Figure 1a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 1b, in early time. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 2a. In Figure 2b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2 and Shot 3.
Fig 1a. Thunder Beast Dominus-SR 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature
Fig 1b. Thunder Beast Dominus-SR 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature
Figure 2a. Thunder Beast Dominus-SR 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
Figure 2b. Thunder Beast Dominus-SR 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
The Thunder Beast Dominus-SR, like the Thunder Beast ULTRA 9 (Review 6.24), produces a significantly unique signature at the weapon muzzle. Signature characteristics typical of Thunder Beast silencers include masking of first-round-pop at the muzzle, which helps to almost nullify the impact of the first shot signature severity differential to the inner ear response of bystanders. The Dominus-SR accomplishes this by expedient quenching of ancillary combustion, evidenced by early rarefaction in the FRP overpressure signature and significantly expressed in the impulse waveforms (Figure 2a). This quenching results in a signature decay that mirrors subsequent shots post-peak, without the positive phase being prolonged relative to later shots.
PEW Science Research Note 1: The same phenomenon described above was observed in PEW Science testing of the ULTRA 9 in the 7.62x51mm combustion regime (SSS.6.24.1.1, Figure 4a), albeit on a barrel almost twice the length of the test shown here (20-in 7.62x51mm bolt action vs. 10.3-in 5.56x45mm MK18). The fact that the TBAC baffle design in the Dominus-SR is still able to quench FRP to bystanders, even from a 10.3-in 5.56x45mm barrel, with a shorter overall silencer length, is notable.
PEW Science Research Note 2: Another notable performance trait of the Dominus-SR on the MK18 is its relatively consistent signature measured at the muzzle, despite the silencer being significantly over-bored for the 5.56x45mm cartridge. Note that the Thunder Beast Dominus-SR is a 30 caliber rifle silencer. Flow consistency with significant over-bore is relatively uncommon without advanced flow paths or significant flow restriction; erratic flow rate characterized in measured impulse signatures from over-bored silencers on the MK18 weapon system may be examined in test reports featuring silencers such as the Rugged Razor762 (6.58), the Energetic Armament ARX (6.82); the Rugged Razor556 (6.76); the Q Trash Panda (6.61), and the Dead Air Sandman-S (6.92).
Less erratic flow rate, despite an even larger over-bore, is possessed by silencers with alternate flow geometry, like the CGS Helios QD (6.66). This silencer is also significantly over-bored, but possesses coaxial flow paths that may be accessed early in its core geometry.
Typically, as a rifle silencer’s bore becomes larger, flow rate increases, all other things equal. However, without complex flow paths, flow rate may still be significantly restricted. This is the case with the Thunder Beast Dominus-SR. See Research Note 3.
PEW Science Research Note 3: The Dominus-SR suppresses overpressure amplitude significantly in early time. As a result, the silencer significantly prolongs the positive phase of the overpressure propagation in the free field. This venting delay, coupled with the unavoidable jetting frequency from its baffle configuration and over-bore, results in gross signature severity that is higher than typical for its measured free field peak overpressure and impulse. The gas propagation delay that initiates the longer positive phase duration can be viewed in impulse space in Figure 2b, above, at a time of between approximately 29.9 and 30.4 ms. At this time, flow stagnates; the subsequent jetting results in another rapid impulse accumulation, after which flow normalizes. This gross behavior has two consequences:
The Thunder Beast Dominus-SR produces a more severe holistic muzzle signature on the MK18 than some other silencers, despite possessing a lower measured peak overpressure amplitude. This is a function of blowdown frequency and duration.
The Dominus-SR produces more significant flow restriction than typical for an over-bored silencer; the flow restriction (back pressure) generation of the Dominus-SR is more similar to that of a YHM Turbo T2 (Review 6.98) than a 30 caliber Dead Air Nomad-30 (Review 6.100) or Dead Air Sandman-S (Review 6.92), for example. This is a function of early time flow rate and blowdown duration.
A pertinent example highlighting the phenomenon in (1) is presented in Section 6.105.2 for PEW Science Members. The case study presents detailed signature comparisons of the Surefire SOCOM556-RC2 (6.52) with that of the Thunder Beast Dominus-SR. Although the SOCOM556-RC2 produces a higher peak measured overpressure, its holistic signature to bystanders is significantly less severe than that from the Dominus-SR.
PEW Science Research Note 4: As in all semiautomatic AR15 weapon testing, a second pressure pulse originates from the ejection-port signature of the weapon and it occurs early enough in time such that its waves coalesce with that of the muzzle signature. However, in late time (at approximately 80 ms in Figure 1a) the mechanical noise of the bolt closing is observed. The pressure signature of Shot 6 does not display this event due to the bolt remaining open after the sixth and final round is fired from the magazine.
PEW Science Research Note 5: The closing time of the MK18 bolt is directly related to the flow restriction of a silencer for a given weapon system. PEW Science has determined bolt closing time variation from the unsuppressed state to be a reliable indicator of silencer back pressure, with strong correlation with the PEW Science Back Pressure Metric, Omega. However, PEW Science has also determined that the indicator is unreliable upon upper receiver fouling. Sound signatures are not influenced by this fouling, as these kinematics occur in late time, after gas venting to atmosphere. Momentum transfer, weapon condition (upper receiver fouling), and other factors, can significantly influence bolt closing time. PEW Science urges the reader to exercise extreme caution if using the published bolt closing time to make determinations regarding silencer flow restriction (back pressure) or weapon system kinematics. This type of calculation may provide erroneous results, as the weapon condition at the time of each test is not published data. The time-scale duration showing bolt closing time is only published by PEW Science such that the signature data pedigree may be verified.
The shape, timing, and magnitudes of the early-time pressure pulses and overall shape of the impulse waveforms measured at the muzzle, from shot-to-shot, are relatively consistent. The consistency of the waveform amplitudes highlight the silencer’s overall sound performance consistency at the muzzle after the FRP, as well as the relative consistency of the tested automatic rifle firearm configuration.
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 Research Note 6: Note that the muzzle Suppression Rating of the Thunder Beast Dominus-SR with the SR brake mount is 24.5 and the at-ear Suppression Rating is 19.3; the same zone on the Suppression Rating Dose Chart. The lower flow rate (higher back pressure) of the Thunder Beast Dominus-SR contributes to both a longer blowdown duration and a more severe ejection port signature, increasing the overall severity of the signature on the standard MK18 weapon system. This phenomenon also occurs with the YHM Turbo T2, the SilencerCo Saker, and the full-size Polonium on the MK18, albeit more severely. Despite the lower peak pressure and impulse produced by the Dominus-SR, caution should be exercised by the weapon operator.
Holistic signatures, to bystanders and the shooter, are compared in the following section for many rifle silencers on the standard MK18 weapon system.
6.105.3 Suppression Rating Comparison (5.56x45mm from the MK18)
Figure 6 presents a comparison of the PEW Science Suppression Rating of the Thunder Beast Dominus-SR with the SR brake mount to that of other rifle silences on the MK18 automatic AR15 rifle. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.
Figure 6. Suppression Rating Comparisons of the Thunder Beast Dominus-SR and other silencers, Using PEW-SOFT 5.56x45mm Supersonic Test Data and PEW Science Analysis
The preceding Section 6.105.2 in the Member version of this article presents a detailed case study comparing the signatures measured at the muzzle and ear of the Thunder Beast Dominus-SR from this report and the Surefire SOCOM556-RC2 (6.52), and their holistic impact to the shooter and bystanders. That case study is intended to supplement the discussion that follows.
Figure 6 presents the detailed PEW Science Suppression Ratings, computed at the muzzle and ear, for the listed silencers. The Suppression Rating is a holistic parameter that captures human inner ear damage risk potential from a measured impulsive overpressure signature. The parameter may be used with the dose chart at the beginning of this report.
When examining the relative performance of the silencers presented above, the Thunder Beast Dominus-SR is shown to posses a more severe muzzle signature than most dedicated 5.56x45mm silencers on the standard MK18 weapon system. Note that the Dominus-SR is a 30 caliber rifle silencer; when viewed in that context, its Suppression Rating to bystanders is closer to that of some competitors on the MK18, such as the CGS Helios QD (6.66) and even higher in some cases, such as compared with the Dead Air Sandman-S (Review 6.92). However, several other 30 caliber silencers outperform the Thunder Beast Dominus-SR in holistic muzzle suppression on the MK18, including the Q Trash Panda (6.61) and Dead Air Nomad-30 (6.100). The Dominus-SR signature is more severe, despite possessing a lower measured peak transient overpressure than some of the aforementioned silencers on the MK18 weapon system. As discussed in the Member case study and Silencer Sound Standard, this phenomenon is due to the influence of the holistic signature on human inner ear response; the quantities of signature amplitude, phase, frequency, and duration all contribute.
PEW Science Research Note 8: Of particular note is the reduced suppression performance at the shooter’s ear with the Thunder Beast Dominus-SR on the standard MK18 host weapon system, when compared to many of the silencers shown in Figure 6. There are two significant factors driving this reduced performance:
The Thunder Beast Dominus-SR produces a more severe holistic muzzle signature on the MK18 than some other silencers, despite possessing a lower measured peak overpressure amplitude. This is a function of blowdown frequency and duration. Muzzle signature contributes to signature measured at the shooter’s ear.
The Dominus-SR produces more significant flow restriction than typical for an over-bored silencer; the flow restriction (back pressure) generation of the Dominus-SR is more similar to that of a YHM Turbo T2 (Review 6.98) than a 30 caliber Dead Air Nomad-30 (Review 6.100) or Dead Air Sandman-S (Review 6.92), for example. This is a function of early time flow rate and blowdown duration. Excess flow restriction (back pressure) increases the severity of ejection port pressure pulse. This phenomenon, combined with other phenomenon in (1), holistically lower shooter’s ear suppression performance.
The Dominus-SR does not exhibit balanced signature performance on the standard MK18, despite being a 30 caliber silencer. Notably, its shooter’s ear Suppression Rating is on par with that of the Otter Creek Labs Polonium (6.75), despite their significantly different bore diameter. As discussed in the preceding sections of this report, this performance is a function of flow rate and jet duration.
There exist silencers with significantly more advanced flow geometry that, even with a tighter bore aperture, may produce less severe holistic signature to the MK18 weapon operator, bystanders, or both. Such silencers include the HUXWRX FLOW 556k (6.83), KAC 5.56 QDC (6.104), and the CGS SCI-SIX (6.101), and others. All three of the aforementioned silencers achieve balanced performance on the MK18 with differing technologies; the HUXWRX silencer with immediate and continuous venting, the KAC silencer with internal porting and fewer baffles, and the CGS silencer with immediate venting and annular utilization.
It is unusual for an over-bored silencer to exhibit significant flow restriction, but it is also unusual for such a silencer to exhibit such consistent performance on the MK18 weapon system. The Thunder Beast Dominus-SR, like the Thunder Beast ULTRA 9, exhibits demonstrated consistency in PEW Science testing. And, like the ULTRA 9, the Dominus-SR is able to mask FRP to bystanders and produce lower signature peak amplitudes than many silencers on a given weapon system. However, when performing in-depth analysis of the holistic signatures from the silencers, some unfavorable phenomena to human inner ear response are evident. This report summarizes these measured phenomena and they are reflected in the computed holistic Suppression Rating.
6.105.4 Review Summary: Thunder Beast Dominus-SR on the MK18 5.56x45mm AR15 with 10.3-in Barrel
When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the Thunder Beast Dominus-SR mounted with the SR brake mount achieved a composite Suppression Rating™ of 26.0 in PEW Science testing. As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
PEW Science Subjective Opinion:
The Thunder Beast Dominus-SR is a mid-size and lightweight 30 caliber machine gun rated rifle silencer. As a 5.56mm machine gun rated rifle silencer, it may be considered full-size. The Dominus-SR reportedly exhibits significant durability for a titanium rifle silencer, through the use of its engineered sacrificial steel muzzle brake mount. The signature suppression performance of the silencer on the short-barrel MK18 is not as balanced as some other tested rifle silencers, due to its flow rate and other signature factors, examined in this test report.
Like other Thunder Beast rifle silencers, the Dominus-SR is effective at nullifying first-round-pop to bystanders. It is interesting to note that the same phenomenon was reported in PEW Science testing of the Thunder Beast ULTRA 9 silencer. The two silencers share a similar design pedigree.
The performance of the Dominus-SR provides an illustrative example of engineered performance goals balanced with design simplicity, in an extremely high quality package. The overall result is continued performance consistency, across models, across tests. In continuous testing of Thunder Beast rifle silencers by PEW Science, measured peak transient overpressure amplitude is significantly suppressed. This clear design goal, along with expedient quenching of ancillary combustion nullifying first round pop (FRP), remains a hallmark performance-based design attribute of Thunder Beast silencers, observed by PEW Science. However, just as common in the design pedigree, is the flow restriction (back pressure) of the baffle stack design. The flow rate, coupled with measured waveform frequency and phase components, results in holistic signatures that are somewhat more severe than only peak waveform transients would reflect. This test report provides a significant amount of measured test data and analysis illustrating this known phenomenon.
Regardless of its lower holistic signature suppression performance, the Thunder Beast Dominus-SR exhibits both aforementioned unusual signature consistency, as well as unusual reported durability, for a silencer constructed entirely of titanium. As presented by the manufacturer, this durability is due to its stainless steel muzzle brake mount, which acts as a deflecting shield and diffuser, preventing direct muzzle jet impingement on the titanium baffle stack. As noted in many silencer designs, even those using nickel alloys like Inconel, 3-prong flash hiders used on short barrel rifles can focus muzzle jetting and significantly erode or damage early baffles in the stack. With the utilization of a multi-port brake, the Thunder Beast SR system allows for a “sacrificial” part to endure erosion. This design attribute allows the Dominus-SR to reportedly withstand multiple SOCOM SURGE cycles; a degree of durability not typically relegated to silencers with titanium blast baffles with no porting. The restrictive titanium first expansion chamber of the Dominus is able to withstand significant firing schedules with the SR brake mount.
The first-round-pop (FRP) suppression performance of the Dominus-SR is notable, as was that of the Thunder Beast ULTRA 9 tested and analyzed by PEW Science. This design attribute is considered by PEW Science to be a hallmark of Thunder Beast silencer performance.
The mounting system of the Thunder Beast Dominus-SR silencer is relatively simple to operate. After threading the silencer onto the SR brake mount, the locking collar is turned to the “locked” position, which is clearly delineated with engraving. PEW Science testing of this silencer and mount system indicates it is secure, with no observable play, and expedient to operate. Users should note that due to the cam-action of the mounting collar, its geometry will not remain normal to the silencer axis when locked. This “crooked” orientation of the locking collar when locked is not a malfunction or manufacturing issue; it is simply a geometric consequence of the locking system mechanics. When locked, the locking collar is almost flush with the brake mount shoulder. This is important to note, depending on the length of handguard present on the host weapon system.
In this review, the Dominus-SR performance metrics depend upon suppressing a supersonic centerfire rifle cartridge on a short barrel gas-operated rifle, which is an incredibly difficult 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 5.56x45mm cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact. Silencer performance on automatic (reciprocating) rifles depends on many factors. Weapon configuration may significantly influence total suppressed small arm system performance.
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.
