SSS.6.61 - Q Trash Panda and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle
/Q Trash Panda on the MK18 5.56x45mm AR15 with 10.3-in Barrel
The Trash Panda is manufactured by Q. It is a 30 caliber centerfire rifle silencer, intended to suppress most cartridges with projectiles appropriately sized to travel through the bore, including 300 Winchester Magnum. It has a 1.75-inch diameter and is 6.9 inches in length. The silencer mounts to the host firearm with the Q Cherry Bomb muzzle brake. The silencer is tubeless and constructed of titanium, while the muzzle brake mount is constructed of 17-4 PH stainless steel. The silencer weighs 13.9 ounces with the muzzle brake. The Trash Panda can be obtained from Silencer Shop.
This Sound Signature Review contains single-test results using the Q Trash Panda 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 6.61.1 contains contains the Trash Panda test results and analysis.
Section 6.61.2 contains Suppression Rating comparisons of the Trash Panda with the Rugged Razor, and also with dedicated 5.56 mm bore rifle silencers, including the KGM R556, OSS HX-QD 556, SilencerCo Saker 556, and Surefire SOCOM556-RC2 on the MK18.
Section 6.61.3 contains the review summary and subjective PEW Science opinions.
Summary: When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the Q Trash Panda mounted with the Cherry Bomb muzzle brake mount achieved a composite Suppression Rating™ of 28.7 in PEW Science testing. As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
The supersonic .308 performance of the Q Trash Panda is detailed in previous Sound Signature Review 6.4, in which it achieved a Suppression Rating of 33.1.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.61.1 Q Trash Panda Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Trash Panda tested with the Cherry Bomb muzzle 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. 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. Q Trash Panda Sound Metric Summary
6.61.1.1 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 Trash Panda 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 4.
Fig 1a. Q Trash Panda 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature, 28-AUG-2021
Fig 1b. Q Trash Panda 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature, 28-AUG-2021
Figure 2a. Q Trash Panda 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature, 28-AUG-2021
Figure 2b. Q Trash Panda 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature, 28-AUG-2021
The Trash Panda is a tubeless 30 caliber rifle silencer with straight cone baffles. Like other 30 caliber rifle silencers, such as the Rugged Razor (Review 6.58), the Trash Panda is significantly over-bored for the 5.56x45mm weapon platform. In contrast with the Razor, the Trash Panda has significantly more baffles (9 versus 4). This increase in baffle quantity results in more backpressure generation with the Trash Panda, and also higher sound suppression performance, in general.
Despite the higher performance of the Trash Panda in comparison with that of the Razor, a symptom of significant over-bore for the weapon platform remains; erratic impulse variation is noted from shot to shot (Figure 2a), as is significant secondary and tertiary jetting (Figure 1b). As typically indicated, FRP is noted in the extreme initial impulse slope of the first shot. During the second shot, the ancillary combustion from the consumption of air during FRP is not present, resulting in a shallower initial slope, but there is a significant secondary impulse increase (approximately 31 ms, Figure 2b). This impulse variation is postulated to result from the bore aperture and baffle design of the Trash Panda being unable to efficiently contain the secondary combustion from unburnt propellant generated on the short (10.3-inch) barrel 5.56x45mm host weapon. The additive blast pressure and impulse from this secondary burning is characterized for the unsuppressed state of the MK18 in Public Research Supplement 6.51. The event occurs again during Shot 3. It is not until Shot 4 that the signature normalizes. This delay in combustion flow normalization is postulated to be a function of short overall combustion duration of the 5.56x45mm intermediate rifle cartridge interacting with significant over-bore, allowing the jetting to bypass significant portions of the baffle stack geometry.
FRP with the Trash Panda on the MK18 is measurable in both pressure (Figure 1) and impulse (Figure 2), and perceptible by the shooter and bystanders. However, it is not postulated to be significant, in accordance with PEW Science inner ear modeling.
PEW Science Research Note 1: PEW Science postulates that the erratic combustion behavior in Figure 2 may be uncharacteristic of the Trash Panda with 5.56x45mm use through longer barrels. Without secondary burning, the bore aperture and baffle geometry may result in more normalized flow, as measured in 20-in .308 testing of the Trash Panda (Review 6.4). Investigation of this phenomenon is the subject of future testing and analysis.
PEW Science Research Note 2: The Trash Panda may experience higher backpressure than the Rugged Razor on the 5.56x45mm platform than it does, relatively, on the 7.62x51mm platform; this phenomenon is the subject of ongoing internal PEW Science research. Combustion duration and jet diameter interaction with baffle stack over-bore may result in nonlinear scaling of the PEW Science Omega Metric. Regardless of linearity, the relationship is shown to hold true in that the Trash Panda does possess higher flow restriction than the Razor with both cartridges. Research is ongoing. Some silencer designs may exhibit more flow restriction (higher back pressure; higher PEW Science Omega Metric) when combustion duration increases, relative to other designs. Silencer flow rate variation may be nonlinear with respect to pressure and duration.
The flow rate of the Trash Panda is lower than that of the OSS HX-QD 556 in Review 6.54, and the KGM R556 in Review 6.60. The Trash Panda generates more back pressure than those silencers. Preliminary calculations indicate that the Trash Panda is measured to have a PEW Science Omega Metric close to that of the Surefire SOCOM556-RC2 (Review 6.52) on the MK18 weapon platform, indicating 5.56x45mm flow restriction on-par with that of the SOCOM556-RC2. However, the erratic impulse behavior due to significant over-bore may influence the computation of the Omega Metric and is the subject of current PEW Science research.
PEW Science Research Note 3: 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. In late time (at approximately 85 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 4: 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.
Note that the muzzle Suppression Rating of the Trash Panda is 27.2 and the at-ear Suppression Rating is 21.7; the same zone on the Suppression Rating Dose Chart. The Trash Panda produces a significant overall signature on this host weapon system. Comparisons with other silencers on the MK18 weapon system are provided below.
6.61.1.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 6-shot test 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 6 shots are shown in Figure 3. The primary sound signature history is shown on the left. A zoomed-in timescale is displayed on the right, in a sound pressure region of interest for Shot 1 and Shot 2. The real sound impulse (momentum transfer potential) histories at the ear from the same 6-shot test are shown in Figure 4. Full and short timescales are shown.
Figure 3a. Q Trash Panda 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature, 28-AUG-2021
Figure 3b. Q Trash Panda 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature, Short Time Window, 28-AUG-2021
Figure 4a. Q Trash Panda 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature, 28-AUG-2021
Figure 4b. Q Trash Panda 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature Peaks, 28-AUG-2021
Like in the measurements at the muzzle, the FRP from the Trash Panda at the shooter’s ear is not significant on the MK18. Also similar to the measurements at the muzzle, there are waveform indicators measured at the ear consistent with erratic secondary combustion due to its significant over-bore for the MK18. The phenomenon is again measured to normalize after the third shot; Shots 4, 5, and 6 exhibit significantly less pronounced variability in their impulse decay histories (Figure 4a). In addition to illustrating this phenomenon, the presence of the impulse increase in the at-ear waveforms illustrates the combined nature of the at-ear signature on a semiautomatic rifle; the at-ear signature includes muzzle events and is not limited to the ejection port signature. The erratic nature of the gas flow and its duration components also negatively influence the impact on the human inner ear. For example, the Trash Panda is measured to possess lower pressure and impulse than the OSS HX-QD 556 at the ear, on the same platform, but it also exhibits a lower Suppression Rating (the Trash Panda is more damaging to the ear; it is objectively louder on the platform). The Suppression Rating is a holistic sound signature metric that takes into account not only pressure amplitude, but duration, timing, phase, and frequency components of the sound signature. The Rating is an indicator of inner ear response which directly correlates with hearing damage and human perception of sound.
As stated in the preceding section, the erratic combustion behavior in Figure 4 may be uncharacteristic of the Trash Panda with 5.56x45mm use through longer barrels. Without secondary burning, the bore aperture and baffle geometry may produce more normalized flow, as measured in 20-in .308 testing of the Trash Panda (Review 6.4). This type of flow normalization (use of the Trash Panda on longer barrel 5.56x45mm host weapons) is postulated to increase the Suppression Rating in conjunction with the increase in distance of muzzle pressure source to the shooter’s ear.
6.61.2 Suppression Rating Comparison (5.56x45mm from the MK18)
Figure 5 presents a comparison of the PEW Science Suppression Rating of the Q Trash Panda to that of the KGM R556, the Rugged Razor, the OSS HX-QD 556, the SilencerCo Saker 556, and the Surefire SOCOM556-RC2 with two different mounts on the MK18 automatic AR15 rifle. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.
Figure 5. Suppression Rating Comparisons of the Q Trash Panda with the Rugged Razor, KGM R556, OSS HX-QD 556, Saker 556, and SOCOM556-RC2 , Using PEW-SOFT 5.56x45mm Supersonic Test Data
From the above data, it can be concluded that the Trash Panda, with its 30 caliber bore and straight cone baffles, is a relatively inefficient silencer for the MK18 host weapon platform. This inefficiency may not necessarily translate to longer barrel 5.56x45mm host weapons. The at-ear Suppression Rating of the Trash Panda on the MK18 is slightly lower than that of the Surefire SOCOM556-RC2 (6.52) and moderately higher than that of the SilencerCo Saker 556 (6.53), and the Rugged Razor (6.58). Compared with the Surefire silencer, the Trash Panda may exhibit similar flow restriction, but erratic suppression due to significant over-bore; this causes a significant reduction in Suppression Rating at the muzzle on the MK18. When compared with the SilencerCo Saker, the Trash Panda has lower flow restriction (lower back pressure), and the at-ear Suppression Rating is higher, but the Saker is still quieter to bystanders due to its tighter bore. The Rugged Razor, also possessing significant over-bore and less baffles than the Trash Panda, is louder at both the muzzle and the ear, despite having lower back pressure than the Trash Panda. There is a significant benefit of using a purpose-built silencer for a given cartridge; over-bored silencers for 5.56 mm may exhibit an inherent suppression performance disadvantage.
The performance of the straight-cone baffle design in the Q Trash Panda suffers less in the supersonic flow regime with the smaller 5.56x45mm intermediate rifle cartridge on the MK18 test host than it does with the larger 7.62x51mm rifle cartridge on the 20-in barrel bolt action test host. PEW Science postulates this is the result of less pressure stagnation with the smaller cartridge; the combustion duration is below the threshold of pressure saturation for the design. As combustion duration increases with larger, more powerful cartridges, the Trash Panda’s performance drops. This phenomenon is observed in other rifle silencers from Q, including the Q Thunder Chicken (Review 6.20). This represents an efficiency drop that is not present in coaxial designs such as in the Dead Air Nomad (Review 6.43) or CGS Hyperion K (Review 6.28), both of which may become more efficient with magnum rifle rounds due to pressure stagnation relief into coaxial chambers.
Bystanders may perceive the loudness of the Q Trash Panda to be on par with that of the OSS HX-QD 556 (Review 6.54) or KGM R556 (Review 6.60) when fired on the MK18 host weapon. Personnel firing the weapon may experience hearing damage risk on par with that from using the Surefire SOCOM556-RC2 with the 3-prong flash hider.
The coalescing of the ejection port overpressure with the primary muzzle blast exacerbates the severity of the signature at the shooter’s head position. It is not ejection port signature, alone, that dictates the signature measured at the shooter’s head position. The muzzle signature of the Q Trash Panda does influence the at-ear signature of the shooter on this platform. This performance factor is significant on a short barrel automatic weapon system (the MK18).
6.61.3 Review Summary: Q Trash Panda 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 Q Trash Panda mounted with the Cherry Bomb muzzle brake mount achieved a composite Suppression Rating™ of 28.7 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 Q Trash Panda is a relatively compact and lightweight 30 caliber silencer that is most efficient when used to suppress intermediate rifle cartridges exhibiting lower combustion pressure and duration. Relative to dedicated 5.56mm bore silencers, it may be considered “full size.” The silencer is intended to be mounted to the host weapon using the Cherry Bomb muzzle brake. It is important to note that the Cherry Bomb acts as a diffusing element which helps to reduce the impingement of combustion products onto the leading edges of the first baffles in the silencer. As the silencer is fully constructed of titanium, the brake may help to prevent significant baffle erosion and will prolong service life when compared to similar silencers that do not utilize a stainless steel brake mount, on shorter barrels. The durability of titanium silencers used with heat-treated stainless steel blast-shielding muzzle brakes has not been experimentally evaluated by PEW Science and is a subject of continued research interest.
The performance of the straight-cone baffle design in the Q Trash Panda suffers less in the supersonic flow regime with the smaller 5.56x45mm intermediate rifle cartridge on the MK18 test host than it does with the larger 7.62x51mm rifle cartridge on a 20-in barrel bolt action test host, for example. PEW Science postulates this is the result of less pressure stagnation with the smaller cartridge; the combustion duration is below the threshold of pressure saturation for the design. As combustion duration increases with larger, more powerful cartridges, the Trash Panda’s performance drops. This phenomenon is observed in other rifle silencers from Q, including the Q Thunder Chicken. This represents an efficiency drop that is not present in coaxial designs such as in the Dead Air Nomad or CGS Hyperion K, both of which may become more efficient with magnum rifle rounds due to pressure stagnation relief into coaxial chambers.
The large bore aperture relative to the 5.56x45mm cartridge results in the Trash Panda exhibiting significant “over-bore” for the MK18 weapon system. This results in erratic gas dynamics that only normalize late in the firing schedule. The practical consequence of this behavior on system performance is more severe sound signature and potentially erratic flash signature on the tested platform.
The Cherry Bomb muzzle brake is relatively lightweight and facilitates straightforward and secure attachment of the silencer to the host weapon with excellent alignment. Users should note that there are third-party mounts available that mimic the thread and taper geometry of the Cherry Bomb. The use of third-party mounts may result in different combustion flow dynamics within the silencer and impact performance. PEW Science highly recommends contacting the silencer manufacturer regarding the efficacy of third-party mount use with the Trash Panda.
In this review, the Q Trash Panda 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.
