SSS.6.180 - Centurion Arms Maximus-L and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle
/Centurion Arms Maximus-L on the MK18 5.56x45mm AR15 with 10.3-in Barrel
The Maximus-L is designed by Centurion Arms. It is a 223 caliber centerfire rifle silencer, intended to suppress the 5.56x45mm cartridge with semiautomatic or fully automatic fire. The Maximus-L has a 1.62-inch diameter and is 6.2 inches long. The silencer may be attached to a variety of weapon systems depending on the user’s choice of mount; a mount is not included. Various mounting options are possible due to the rear of the silencer body being HUB compatible (1.375”-24 tpi threading). The entirety of the Maximus-L structure is monolithic and constructed from 3D Printed Inconel alloy. The silencer weighs 14 ounces, and with a Rearden titanium direct-thread mount, weighs 14.8 ounces and is 6.4 inches long, as tested. The Maximus-L can be obtained from Centurion Arms.
PEW Science is an independent private testing laboratory and also hosts the world’s only independent public suppressed small arms research cooperative. Testing, data analysis, and reporting is generated with funding provided by PEW Science members. Any test data that is generated with any portion of private funding contains this disclosure. The testing and analysis production for this Sound Signature Review was funded in part by PEW Science Project PEW-Centurion-102-001-24. Therefore, data pertaining to the Maximus-L in this Sound Signature Review is published with the express written permission of Centurion Arms LLC.
The testing and analysis presented in this Sound Signature Review are of the Maximus-L on the MK18 Automatic AR15 rifle 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 6.180.1 contains Maximus-L test results and analysis.
Section 6.180.2 contains overall Suppression Rating comparisons of the Maximus-L with with dedicated 223 and 30 caliber silencers on the current market, including the Otter Creek Labs Infinity, PTR VENT Spiritus 556i, LMT AT ION LT, HUXWRX FLOW 556 Ti, Off Grid Operator Ti, Surefire SOCOM556-MINI2, KAC QDC/CRS-PRT, KAC QDC/MCQ-PRT, Surefire SOCOM556-RC3, Otter Creek Labs Polonium-30, AAC M4-2000 Mod 08, PTR VENT 3, SilencerCo Velos LBP, BOSS Guillotine, CAT WB, PWS BDE 556, CAT ODB, Aero Precision Lahar-30L, Lahar-30, HUXWRX FLOW 762 Ti, Maxim Defense DSX, Thunder Beast Dominus, 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 6.180.3 contains an article summary and PEW Science laboratory staff opinions.
Summary: When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the Centurion Arms Maximus-L with direct-thread mount achieved a composite Suppression Rating™ of 40.3 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
6.180.1 Centurion Arms Maximus-L Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Centurion Arms Maximus-L 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. Centurion Arms Maximus-L Sound Metric Summary
6.180.1.1 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 public dataset and bolt-closing signatures. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science laboratory sound signature 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 laboratory testing; the recognized 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 Centurion Arms Maximus-L 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 Shots 2 and 3.
Fig 1a. Centurion Arms Maximus-L 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature
Fig 1b. Centurion Arms Maximus-L 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature
Figure 2a. Centurion Arms Maximus-L 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
Figure 2b. Centurion Arms Maximus-L 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
The Centurion Arms Maximus-L is yet another example of a hybrid design silencer. In the PEW Science Research taxonomy, hybrid design silencers are those in which elements of both conventional and high flow rate silencers are used, coupled with other technology variations and staged elements to provide parametrically varied performance attributes. Such attributes include the ability to reduce impulse accumulation from early-time shock reflections while significantly altering the rate of proximal and distal venting. These silencers may allow for minimal reciprocating weapon functional influence, while at the same time significantly suppressing signature to the operator and bystanders. Hybrid designs span a large range of the market in both brand and performance in different combustion regimes. There also exist subcategories of this class of silencers that have been shown to demonstrate efficacy in multiple flow regimes. Discussion of these subcategories is outside the scope of this report. Other hybrid designs and staged hybrids include those from PTR, CAT, CGS, SilencerCo, Surefire, updated recent Dead Air and Otter Creek Labs models, and others. For an overview of the three primary classes of rifle silencer designs, the reader is encouraged to review PEW Science Research Supplement 6.169.
Unlike some other hybrids that have distinct pressure staging (“staged hybrids” such as those from CGS, CAT, and now Otter Creek Labs in the Infinity), the Centurion Arms Maximus-L is an example of a standard hybrid. In fact, its primary baffle geometry consists of standard uniformly ported cones. Nonetheless, the holistic design of the Maximus-L reveals certain advanced features that, together, result in extremely high performance potentials for the design envelope:
Complete circumferential closely-proximal venting array in the first expansion (blast) chamber.
Double-curvature and direct porting of the first reflector (blast baffle) that, along with (1), prevents excessive blast load impulse accumulation in early time.
Significant annular utilization; 36 annular vent paths fed by the circumferential proximal vent array, each with internal spiraled geometry, both relieve initial stagnation and significantly increase turbulence and heat transfer.
Venting in each baffle, with minimal, but additive, direct-venting at the distal end, in addition to primary bore venting.
PEW Science Research Note 1: The Centurion Arms Maximus-L performance data acquired in this test indicates that an extremely high degree of performance efficacy can be achieved with the addition of geometric features occupying a relatively low volumetric portion of the design envelope. It is important to note that the Maximus-L is only 6.2 inches long and weighs 14 ounces, without a mount, and is constructed of an Inconel alloy; not a lightweight alloy like titanium or aluminum. Furthermore, the primary baffle array consists of standard ported cones. It is the extremely efficient use of the relatively small annular cavities that allows for significant muzzle blast suppression with high flow rate; a performance combination that is typically only achieved in hybrid designs. However, with the positive high-performance attributes, there are also some performance compromises resulting from some of the design simplicities. Both are illustrated in distinct features of the blast load test data acquired in the free field, 1.0 m left of the silencer’s distal end:
Relatively moderate blowdown duration (Fig. 1a).
Typical early-time positive phase duration with consistent initial coupled jetting (Fig. 1b).
Significant early first-round-pop (FRP) jetting with accompanied rarefaction, followed by additional severe jetting and divergence (Fig. 1b and Fig. 2b).
Relatively early diminished blast pressure amplitude (Fig. 1b).
Decreased momentum accumulation rate characterized by less blast load impulse accumulation post-FRP, with accumulation rates elevating later in the shot string (Fig. 2b).
Some of the observed gross behaviors are indicative of a design that would typically be characterized as “high back pressure,” but the Maximus-L has been augmented with advanced (and efficient) high-flow features. The Centurion Arms Maximus-L, in principle, is one of the purest examples of hybrid design efficiency in the research pedigree with its primary stage simplicity. FRP and performance stability are phenomena that highlight some performance detriment. The following two Research Notes provide additional commentary.
PEW Science Research Note 2: The FRP signature, to which bystanders adjacent to the muzzle of the weapon system will be exposed, is relatively severe when compared to that of subsequent shots. This signature severity, over three times as severe than that of follow-up shots, is seemingly driven by both short barrel combustion severity and unimpeded volumetric expansion through ancillary venting. Further internal PEW Science laboratory evaluations indicate, preliminarily, that there may be a critical blast load input amplitude by which the FRP phenomena is exacerbated through this particular silencer. This postulation is supported by the multiple pronounced FRP momentum accumulation peaks observed in this test data (impulse space, Fig. 2b, prior to maximum). Forthcoming longer-barrel system test results do not display as severe of an FRP signature severity differential. Additionally, all evaluations have been conducted with direct-thread mounting. It is also possible that FRP signature may be altered with other mounting solutions, though other performance variations may also occur, including in both early- and late-time flow rate. Further research is needed.
PEW Science Research Note 3: As discussed, another potential performance detriment of some of the design simplicities in the Maximus-L is consistency, or “performance stability.” After shot 2, which exhibits reduced blast momentum accumulation, propagation stabilizes throughout the string. This initial lack of consistency is, again, isolated to short-barrel combustion propagation in accordance with PEW Science testing. With longer barrels, post-FRP blast propagation is immediately stabilized. It is important to note that some of this inconsistency likely results from thermal stabilization; this postulation is supported by engineering calculations showing increased severity potentials at the end of the string. The array of spiraled annular vents are completely decoupled from late time blast propagation, though they do share common barrier walls.
PEW Science Research Note 4: The Centurion Arms Maximus-L, on average, exhibits extremely high performance on the standard untuned 10.3-in barrel MK18. Its combination both of both muzzle (bystander) signature suppression and shooter’s ear (operator) suppression capabilities is nontrivial. With an overall Composite Suppression Rating of 40.3, it has the third highest overall performance in the current research pedigree Rankings. It’s muzzle Suppression Rating is 39.8, placing it in the top 5 for bystander protection. It’s shooter’s ear Suppression Rating is 28.5, placing it in the the top 10 for operator protection. This performance combination is notable, particularly for a silencer of this size and weight. And, as a hybrid design, the Maximus-L exhibits significant distal momentum control. The benefits of this performance trait are further discussed at the end of Research Note 5.
PEW Science Research Note 5: It is worth listing various other technologies in the hybrid design taxonomy. Differential flow rates in early and late-time are common characteristics of advanced hybrid designs in which elements of high flow rate designs are combined with more traditional geometries to throttle the rate of combustion gas propagation late enough in the time regime so weapon operation is influenced to a lower degree. Other examples of hybrid technologies and hybrid designs examined in the Standard research pedigree include (but are not limited to):
CGS Hyperion Technology - Hyperion (6.27), Hyperion K (6.28), Helios QD (6.13), SCI-SIX (6.101)
Surefire Total Signature Reduction - SOCOM556-RC2 (6.52), SOCOM762-RC2 (6.26), SOCOM556-RC3 (6.151), SOCOM-556-MINI2 (6.144)
CAT SURGE BYPASS - CAT ODB (6.120), CAT WB (6.129)
Liberty Precision Machine Tech - Torch (6.126)
SilencerCo LBP - Velos LBP (6.134)
PTR Purposely Induced Porosity (PIP) - VENT 3 (6.135), VENT Spiritus 556i (6.175)
KAC Pressure Reduction Technology (PRT) - KAC 556 QDC/CRS-PRT (6.156), KAC 556 QDC/MCQ-PRT (6.156)
FOR Systems Tech - Monarch 7.62 (6.155)
Sig Sauer Forward Flux - SLH300Ti (6.107)
Otter Creek Labs New Generation - Infinity (6.179)
Dead Air Triskelion Technology - Mojave 9 (6.177)
Again, the above are classified as hybrid designs in the PEW Science research taxonomy. None of the above technologies or silencers are “Flow-Through” designs. That technology is only available from HUXWRX, and its principles of operation differ significantly from all of the above. Although some of the above silencers may be marketed as “Flow-Through” silencers by dealers and distributors that sell products, the physical mechanisms and performance differentials between all of the technologies are significant. The reader is highly encouraged to examine the in-depth laboratory testing and analysis of HUXWRX systems for a detailed description of pertinent behavioral factors. For example, when distal gas velocity increases significantly, as it does in a true Flow-Through design, there are consequences to the sound field that may induce unfavorable frequency components and reflection phenomena. The Research Caution at the beginning of this FLOW 556 Ti test report elaborates on this phenomenon, with additional research references available.
PEW Science Research Note 6: It is extremely important for the reader to understand the Suppression Ratings are computed with free field test data, and are therefore universal when translating the weapon and operator to different environments without reflections. However, when the environment becomes complex with many reflecting surfaces, performance translation of different systems is not yet possible; sound field shapes and particle velocities result in varied blast wave time-of-arrivals, as well as changes of blast load angles of incidence; these variations change amplitude and phase waveform components. As a result of these inevitable environmental complexities, user impressions will vary, as both the shooter and bystander. Nonetheless, hazard reduction efficacy in the free field, as characterized by the Suppression Rating, holds. The Suppression Rating comparisons are the current state-of-the-art, and the most “apples to apples” sound suppression performance comparisons that currently exist. Further research is ongoing.
PEW Science Research Note 7: 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 95 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 8: The closing time of the AR15 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 and the alpha parameter. 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 9: Note that the muzzle Suppression Rating of the Centurion Arms Maximus-L is 39.8 and the at-ear Suppression Rating is 28.5; different zones on the Suppression Rating Dose Chart. The lower back pressure of the Maximus-L does contribute to a less severe ejection port blast signature, and the simple gas throttling technology in the silencer does slow blast propagation to reduce bystander hazard. The back pressure is low enough to reduce the ejection port blast loads to the shooter more significantly than with most other silencers on the standard MK18 weapon system. Weapon tuning may influence hazard reduction efficacy, and is outside the scope of this study.
The signatures measured at the shooter’s ear are presented and analyzed below.
6.180.1.2 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 in Figure 3a. An annotated timescale is displayed in Figure 3b, for Shots 1, 2, and 3. The real sound impulse (momentum transfer potential) histories at the ear from the same 6-shot test are shown in Figure 4. Again, full and shorter timescales are shown.
Figure 3a. Centurion Arms Maximus-Li 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature
Figure 3b. Centurion Arms Maximus-L 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature, Short Time Window
Figure 4a. Centurion Arms Maximus-L 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature
Figure 4b. Centurion Arms Maximus-L 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature Peaks
Immediate and clear signs of low back pressure behavior are observed in the test data presented above:
Expedient blowdown from shorter-duration muzzle blast propagation (Fig. 3a).
Significantly reduced blast load amplitude decay in early time (Fig. 3b).
Front-loaded FRP blast load impulse (Fig. 4b).
Distinct and consistent entrance into blast impulse negative phase (Fig. 4a).
Like other high performance hybrid designs, the Centurion Arms Maximus-L displays clear signs of low back pressure silencer behavior in the measured blast overpressure data at the operator’s head.
Front-loaded FRP occurs in conjunction with the primary blast back-loaded FRP, as noted in Figure 4b. First presented in the evaluation of the Maxim Defense DSX on the MK18 and the tuned MK18 SURG system (reports 6.110 and 6.111, respectively), clear delineation of front-loaded FRP at the shooter’s ear is direct evidence of lower adverse ejection port blast amplitude. This relative determination is possible due to the continuum of impulse accumulation from the multiple blast sources at the operator’s head, and the use of a standardized host weapon test platform. Report 6.111 shows an extreme case, in which the gas port orifice is restricted significantly (the upper is tuned). For front-loaded FRP to occur on the untuned MK18 is often a hallmark of low back pressure performance. This is corroborated by the 28.5 shooter’s ear Suppression Rating of the Maximus-L.
PEW Science Research Note 10: It is interesting to note that the significant FRP muzzle blast signature from the Maximus-L does elevate the measured blast load amplitude at the operator’s head. However, unintuitively, the relative FRP severity to the operator is significantly lower than that calculated for bystanders adjacent to the weapon system. It is postulated that the remaining ejection port blast hazard still dominates that portion of the pressure field. This is important because it shows that even high flow rate silencers may not completely mitigate the dominant effects of ejection port muzzle blast to the operator. This hazard may be reduced, but it is most certainly not eliminated.
PEW Science Research Note 11: It is likely that the main portion of the Maximus-L design, without its hybrid annular components, would perform exceedingly well in pure muzzle suppression. However, it is also likely that the backpressure from such a design would result in exceedingly high operator hazard.
Operator hazard reduction is a function of all system parameters. It is also important to note that the above discusses only blast overpressure hazard reduction. Gas toxicity hazards, even if reduced by weapon tuning, will most likely not be reduced to the lower levels of extremely high flow rate silencers with a typical high back pressure model. This is particularly the case with rapid fire weapon operation, etc, in which the environment for expanding combustion gasses in the silencer becomes super-heated and downstream expansion is limited. This is sometimes colloquially referred to as the “gas stack” phenomenon.
Due to the design of the Maximus-L, it is likely that users will experience less “gas stack” than with legacy designs. Rate of fire is a significant variable of consideration with regard to the severity of that phenomenon.
PEW Science Research Note 12: The AR-15 weapon system, in general, is extremely hazardous the weapon operator, even when suppressed. Ejection port blast loads are severe. Tuning of the system by increasing buffer mass, decreasing gas port orifice area, or both, may reduce the amplitude and duration of ejection port blast loads from the weapon chamber. Reduction in severity from such weapon tuning is highly nonlinear and will vary based on silencer and weapon.
6.180.2 Suppression Rating Comparison (5.56x45mm from the MK18)
Figure 5 presents a comparison of the PEW Science Suppression Rating of the Centurion Arms Maximus-L with that of several other silencers on the MK18 weapon system. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.
Figure 5. Suppression Rating Comparisons of the Centurion Arms Maximus-L and other rifle silencers, Using PEW-SOFT 5.56x45mm Supersonic Test Data and PEW Science Analysis
Figure 5 presents an overall summary of the postulated hazards to the operator and bystanders when fielding a variety of different silencers on the standard MK18 weapon system. The Centurion Arms Maximus-L from this test program is shown in red. Hazards are expressed with the Suppression Rating; a holistic parameter that captures human inner ear damage risk potential from a measured impulsive complex blast overpressure signature during the entire time regime of weapon operation, including combustion, complete blowdown, and all mechanical operation, including the carrier group returning to battery, in the true free field. The parameter may be used with the dose chart at the beginning of this report. The PEW Science Suppression Rating is a damage risk criterion (DRC), a lower Suppression Rating indicates a higher personnel hazard in the free field - it is not a subjective quantity; it is an objective quantification of hearing damage risk potential. Due to its true free field test data origin and complete waveform analytical calculation basis, it is the only known universal suppressed weapon system signature comparison metric available. Analytically computed metrics are color-coded in the Rankings Table and keyed to the dose chart for user interpretation.
The following gross conclusions can be made from the metrics presented in Figure 5, above:
The Centurion Arms Maximus-L produces free field bystander hazard reduction on par with that of several other high performance silencers as the solid 5.56 end cap Otter Creek Labs Infinity (6.179), HUXWRX FLOW 556 Ti (6.167), and Otter Creek Labs Polonium (6.75).
The free field operator (shooter) hazard reduction of the Maximus-L with the standard untuned MK18 weapon system is elevated beyond most systems, including hybrid systems, such as the aforementioned Otter Creek Labs Infinity. The Maximus-L outperforms most standard and conventional baffle system silencers in shooter hazard reduction on this platform, including the Infinity, despite both silencers achieving relatively comparable free field bystander hazard reduction. All Polonium series silencers are outperformed by the Maximus-L on the standard MK18 in operator hazard reduction due to their high backpressure. The higher early-time flow rate of the Centurion Arms design allows for significantly less ejection port blast propagation than most silencers on the standard untuned MK18. It is important to note that the PTR VENT 3 (6.135) outperforms the Maximus-L in both muzzle and shooter’s ear suppression performance, though the VENT 3 is considerably longer than the Maximus-L. When the PTR purposely induced porosity (PIP) technology is utilized in the shorter design envelope of the PTR VENT Spiritus 556i (6.175), more significant gains in operator risk reduction over the Maximus-L are realized.
Performance comparisons of the Centurion Arms Maximus-L with silencers featuring CAT Surge Bypass technology are interesting in that the somewhat longer 30 caliber CAT ODB (6.117) nominally eclipses the operator hazard reduction of the Maximus-L on this weapon system, but falls short in bystander suppression performance. The shorter 5.56-dedicated CAT WB (6.129) almost matches the operator hazard reduction, while again, having lower adjacent bystander risk reduction. Both of the CAT silencers exceed the consistency and FRP reduction performance metrics of the Maximus-L, illustrating some of the greater degree of performance potentials in the Surge Bypass technology, as well as the strong efficacy of the Centurion Arms design.
Overall, in both bystander and operator protection, the Centurion Arms Maximus-L significantly outperforms legacy designs such as the Q Trash Panda (6.61). Although smaller diameter, the Maximus-L does share the straight ported cone geometry of the Trash Panda; however, with its additional hybrid design components, the two silencers are significantly different. Other primitive designs like the Energetic Armament ARX (6.82) and Rugged Razor 762 (6.58) produce a degree of personnel hazard that may be considered severe when compared to that of the Maximus-L. Although the Surefire SOCOM556-RC2 (6.52) has similar distal momentum control, the Maximus-L exceeds its hazard reduction performance in most metrics, in a lighter envelope.
With an overall Composite Suppression Rating of 40.3, the Centurion Arms Maximus-L has the third highest overall performance in the current research pedigree Rankings. It’s muzzle Suppression Rating is 39.8, placing it in the top 5 for bystander protection. It’s shooter’s ear Suppression Rating is 28.5, placing it in the the top 10 for operator protection. This performance combination is notable, particularly for a silencer of this size and weight.
PEW Science Research Note 13: As previously discussed, the Centurion Arms Maximus-L performance data acquired in this test indicates that an extremely high degree of performance efficacy can be achieved with the addition of geometric features occupying a relatively low volumetric portion of the design envelope. It is important to note that the Maximus-L is only 6.2 inches long and weighs 14 ounces, without a mount, and is constructed of an Inconel alloy; not a lightweight alloy like titanium or aluminum. Furthermore, the primary baffle array consists of standard ported cones. It is the extremely efficient use of the relatively small annular cavities that allows for significant muzzle blast suppression with high flow rate; a performance combination that is typically only achieved in hybrid designs. The combination of size, weight, suppression performance, and hazard reduction for both shooter’s and bystanders is notable. The evolution of hybrid designs continues, and is expected to continue to increase performance dividends on semiautomatic host weapons.
As detailed in this report, signature at the operator’s head is a function of both muzzle and ejection port signatures from the AR-15 weapon system. Specific weapon system parameters will dictate modification efficacy.
Small arm weapon system suppression performance is a spectrum. The PEW Science Suppression Rating and the Silencer Sound Standard help quantify this spectrum for end users and industry, objectively.
6.180.3 Review Summary: Centurion Arms Maximus-L 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 Centurion Arms Maximus-L with direct-thread mount achieved a composite Suppression Rating™ of 40.3 in PEW Science testing.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
PEW Science Laboratory Staff Opinion:
The Centurion Arms Maximus-L is a full size 5.56mm machine gun rated rifle silencer that exhibits high signature suppression performance and back pressure reduction in a lightweight envelope. Constructed entirely of 3D-printed Inconel alloy, the HUB-mountable Maximus-L also exhibits significant durability to compliment its high degree of both bystander and operator hazard reduction on the standard MK18 weapon system. As a hybrid design with high flow rate, the silencer allows for high performance in a variety of environments.
The Centurion Arms Maximus-L performance data acquired in this test indicates that an extremely high degree of performance efficacy can be achieved with the addition of geometric features occupying a relatively low volumetric portion of the design envelope. It is important to note that the Maximus-L is only 6.2 inches long and weighs 14 ounces, without a mount, and is constructed of an Inconel alloy; not a lightweight alloy like titanium or aluminum. Furthermore, the primary baffle array consists of standard ported cones. It is the extremely efficient use of the relatively small annular cavities that allows for significant muzzle blast suppression with high flow rate; a performance combination that is typically only achieved in hybrid designs. The evolution of hybrid designs continues, and is expected to continue to increase performance dividends on semiautomatic host weapons.
Although there are some FRP and consistency anomalies noted with the Maximus-L in short-barrel combustion evaluations, its overall performance is strong and does scale to longer barrel lengths with less propensity for these anomalies to manifest. With an overall Composite Suppression Rating of 40.3, the Centurion Arms Maximus-L has the third highest overall performance in the current research pedigree Rankings. It’s muzzle Suppression Rating is 39.8, placing it in the top 5 for bystander protection. It’s shooter’s ear Suppression Rating is 28.5, placing it in the the top 10 for operator protection. This performance combination is notable, particularly for a silencer of this size and weight.
The spiraled flow paths in each of the 36 annular vent paths of the Maximus-L are a major performance contributor in the design. It is postulated it is critical that these flow paths remain free of debris; PEW Science has not evaluated the Maximus-L after long-duration firing schedules. Any maintenance schedules required for the silencer should be verified with the manufacturer by the end-user. It may be likely that debris buildup is not a significant concern with the design; the flow channels are not particularly arduous.
It is likely that the durability of the Centurion Arms Maximus-L is higher than many silencers on 5.56 NATO weapons. Due to its Inconel construction, the system is more resistant to particle erosion from high temperature and pressure jet impingement. Centurion Arms indicates that the silencer successfully passes 10 SOCOM firing schedule tests, each of which are 8-magazine evaluations with different rates of fire.
The Centurion Arms Maximus-L is HUB mount capable. The user may adapt the silencer to a variety of mounting systems of their preference.
In this review, the Centurion Arms Maximus-L 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.
