SSS.6.166- Off Grid Suppressors Operator Ti and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle (Free Version)
/Off Grid Suppressors Operator Ti on the MK18 5.56x45mm AR15 with 10.3-in Barrel
The Operator Ti is a centerfire rifle silencer from Off Grid Suppressors (Off Grid), intended to suppress the 5.56x45 mm NATO cartridge. It has a 1.5-inch diameter and is 6.6 inches long. The proximal end of the silencer is threaded 1/2-28 tpi for direct-thread mounting only. The silencer is 3D printed from a titanium alloy, and weighs 8.4 ounces, as tested. The silencer is also available in a 3D-printed Inconel alloy model, with an increased weight of approximately 15.5 ounces. The Operator models can be obtained from Off Grid Suppressors and Silencer Central.
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-OG-089-001-24. Therefore, data pertaining to the Operator Ti in this Sound Signature Review is published with the express written permission of Rough Rider Technology.
The testing and analysis presented in this Sound Signature Review are of the Operator Ti 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 6.166.1 contains Operator Ti test results and analysis.
Section 6.166.2 contains overall Suppression Rating comparisons of the Operator Ti with with dedicated 223 and 30 caliber silencers on the current market, including the 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 6.166.3 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 Off Grid Suppressors Operator Ti achieved a composite Suppression Rating™ of 37.4 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
6.166.1 Off Grid Suppressors Operator Ti Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Off Grid Suppressors Operator Ti 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 public PEW Science testing, research, and development with a membership, here. State-of-the-art public firearm sound signature testing and research conducted by PEW Science is supported by readers like you.
Table 1. Off Grid Suppressors Operator Ti Sound Metric Summary
6.166.1.1 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 Operator Ti 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. Off Grid Suppressors Operator Ti 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature
Fig 1b. Off Grid Suppressors Operator Ti 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature
Figure 2a. Off Grid Suppressors Operator Ti 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
Figure 2b. Off Grid Suppressors Operator Ti 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
As discussed in the test report of the larger 30 caliber Off Grid Trident Ti with 7.62 NATO (6.165), the Off Grid family of silencers consists of monolithic 3D printed direct thread models, most of which incorporate internal geometry indicative of modern hybrid technology. Hybrid silencers combine elements of conventional baffle designs with high flow rate geometries such as those implemented in HUXWRX Flow-Through technologies, and others. The performance of several different hybrid silencer technologies is examined in Member Research Supplement 6.124.
Like the 30 caliber Trident Ti, the smaller 5.56 mm Off Grid Operator Ti possesses a ported conventional blast baffle which feeds a relatively complex toroidal spiral internal structure, terminating with additional distal vents. In contrast to Flow-Through technologies, the blast propagation from the distal end of a silencer possessing a hybrid technology may possess different characteristics, even if it possesses distal venting ancillary to the bore. In a gross sense, this is due to a lower flow rate facilitated by early time blast load reflections and subsequent stagnation.
Similar characteristics observed in the testing of the Off Grid Trident Ti in the 7.62 NATO combustion regime are observed in the test data of the Operator Ti with 5.56 NATO. Although they present slightly differently due to different combustion pressure, duration, and barrel length, many behaviors are mirrored, along with their differences from Flow-Through silencers, such as:
Relatively longer blowdown duration (Fig. 1a).
Lack of decoupled ground reflection, consistent with (1).
Relatively short initial positive phase blast load duration with coincident rarefaction (Fig. 1b).
Blast pressures reach maxima later in time, post-initial jetting (Fig. 1b).
Relatively longer duration rise to maximum positive phase blast impulse (Fig. 2a).
The same blast load accumulation plateau measured with the Trident Ti is also noted with the Operator Ti (~30.2 ms, Fig. 2b). This flow normalization and throttling is, again, significantly different than that observed with HUXWRX Flow-Through silencers. The reader is encouraged to compare and contrast the behavior of the Off Grid Operator Ti in this combustion regime with that of the HUXWRX FLOW 762 Ti (6.114), the HUXWRX FLOW 556k (6.83), the HUXWRX (OSS) HX-QD 556 (6.54), and the HUXWRX (OSS) HX-QD 556k (6.64). In all cases, the Flow-Through technology demonstrates significantly different behavior than that of the hybrid geometry in the Operator Ti. Impulse decay onset duration, post-peak, is one of the most significant differences, along with initial positive phase blast duration. In the case of the FLOW 762 Ti, impulse decay is prolonged, but the plateau duration at peak amplitude is shorter.
PEW Science Research Note 1: The Operator Ti provides relatively balanced suppression performance with flow rate. Typically, hybrid designs are required for this type of performance balance. The closest performance competitor to the Off Grid Operator Ti, in the size class, is the CAT WB (6.129). The CAT WB is a “k” model that is shorter, HUB-mountable, and lighter; its titanium version is even lighter than the lightweight Operator Ti tested herein. Nonetheless, both silencers exhibit high performance to both bystanders and the operator, in the free field. Both silencers produce nominal first-round-pop (FRP) severity differentials to bystanders on the MK18 platform.
PEW Science Research Note 2: The Off Grid hybrid technology is somewhat different than CAT SURGE BYPASS implemented in the WB. Whereas SURGE BYPASS is a distinctly staged hybrid design, the Off Grid toroidal spirals are relatively similar in axial progression, with somewhat constricted expansion ratios toward the distal end. This type of staged array is more common, and somewhat more simple in implementation. The performance dividends are still present, but increased length is required to achieve the desired performance in the Off Grid silencers. This is one of the primary practical differences in the two technologies. Another difference between the technologies is the early time flow rate. The ported first reflector (blast baffle) of the Operator Ti induces greater impulse accumulation than the larger and more complex vent arrays in SURGE BYPASS hybrid designs like the CAT WB. Therefore, operator protection with the CAT WB, ODB, and others, is likely to be higher than experienced with the Off Grid silencers on the same given host weapon systems.
PEW Science Research Note 3: It is interesting to compare the performance of silencers in this size class (less than 6.6 inches long), on the standard 5.56 MK18 weapon system. In addition to the the CAT WB, competitors include the CGS SCI-SIX (6.101), Surefire SOCOM556-RC2 (6.52), Liberty Precision Machine Torch (6.126), Otter Creek Labs Polonium (6.75), and PWS BDE 556 (6.123). Of those competitors, the SCI-SIX and Torch provide the most balanced performance. The RC2, Polonium, and BDE systems possess higher back pressure.
PEW Science Research Note 4: Other than the noted FRP combustion propagation differential, the consistency of the Off Grid Operator Ti is notable. The blast impulse accumulation histories measured and reported in Figure 2 remain consistent throughout the shot string, even into Shot 6. This is in contrast with the measured impulse accumulation from HUXWRX Flow-Through designs that often exhibit higher amplitudes with system heating. This difference in behavior is somewhat expected, given that heat transfer over long flow path length is a significant mechanism of Flow-Through silencer performance and the Off Grid silencers trade path duration for stagnation duration. The performance driver for the Off Grid systems appears to be the reduction in volumetric expansion toward the later stages of the toroidal spirals. These types of design differences continue to highlight the various methods by which supersonic rifle suppression, and its balance with gross flow rate, has advanced in recent years.
PEW Science Research Note 5: 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 83 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 6: 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 7: Note that the muzzle Suppression Rating of the Operator Ti is 36.9 and the at-ear Suppression Rating is 25.6; different zones on the Suppression Rating Dose Chart. The lower back pressure of the Operator Ti contributes to a less severe ejection port blast signature. However, the the back pressure is not low enough to reduce the ejection port blast loads to the shooter as significantly as with some 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 in the Member version of this article.
6.166.3 Suppression Rating Comparison (5.56x45mm from the MK18)
Figure 5 presents a comparison of the PEW Science Suppression Rating of the Off Grid Operator Ti 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 Off GRid Operator Ti 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 Off Grid Operator Ti 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 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.
The following gross conclusions can be made from the above:
The Off Grid Operator Ti produces free field bystander hazard reduction on par with that of the Otter Creek Labs Polonium (6.75) and Aero Precision Lahar-30L (6.119), which both possess higher back pressure.
The free field operator (shooter) hazard reduction of the Operator Ti with the standard untuned MK18 weapon system is on par with that of the CGS SCI-SIX (6.101), vented LPM Torch (6.126), and the previous generation HUXWRX (OSS) HX-QD 556 (6.54). It is important to note that the mechanisms by which the operator hazard reduction on the standard untuned MK18 is achieved with these silencers is different, from model to model. The waveform parameters vary significantly as a result, and the Suppression Rating allows one to distill the overall severity into a single metric for hazard prediction.
The Off Grid Suppressors Operator Ti is 1.5 inches in diameter, and 6.6 inches long; its size envelope is constant due to being only direct-thread mountable. In this size class, its competitors include the CAT WB (6.129), the aforementioned SCI-SIX, Torch, and Polonium, as well as the Surefire SOCOM556-RC2 (6.52) and PWS BDE 556 (6.123). Of those competitors, the CAT WB is the smallest and most balanced, with the the SCI-SIX and Torch also providing a somewhat balanced balanced net performance result on the weapon system. The RC2, Polonium, and BDE systems possess higher back pressure, as discussed in the referenced testing and analysis reports.
In the tested Ti configuration, the Operator Ti weighs only 8.4 ounces. The titanium version of the CAT WB is lighter, and there are no other models in the research pedigree in this size class with a weight in that range. The 5.8-inch long Energetic Armament ARX (6.82) weighs 8.8 ounces in the tested configuration, but its suppression performance is significantly lower on this weapon system, relative to other silencers in the Standard.
The efficacy of the Off Grid silencer technology appears to be strong; its performance, for the size, is notable. While not possessing the highest flow rate of competing technologies, the flow rate and suppression balance is still higher than usual. Weapon system tuning will most likely result in more favorable hazard reduction to the weapon operator.
PEW Science Research Note 10: As noted, again, there are demonstrated benefits in the pursuit of hybrid silencer technology development, over that of Flow-Through implementations. As early time flow rate is elevated, and distal momentum propagation throttled, the balance of both performance attributes continues to produce performance combinations that show promise. Hybrid technologies continue to proliferate in the market; designs like the Surefire SOCOM556-RC3 (6.151), SilencerCo Velos (6.134), CAT WB (6.129), FOR Systems Monarch 7.62 (6.155), and others, are joined by silencers like those from Off Grid to balance suppression performance in multiple environments with higher flow rates to mitigate operator hazards.
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.
6.166.3 Review Summary: Off Grid Suppressors Operator Ti 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 Off Grid Suppressors Operator Ti achieved a composite Suppression Rating™ of 37.4 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 Off Grid Suppressors Operator Ti is an extremely lightweight full size 5.56 mm rifle silencer that demonstrates high performance for its size and weight, with lower back pressure than conventional designs. The silencer is direct-thread-mount only, and is also smaller diameter than many competing models. The silencer is 3D printed, and also available in an Inconel model for use with more severe firing schedules.
The Off Grid family of silencers consists of monolithic 3D printed direct thread models, most of which incorporate internal geometry indicative of modern hybrid technology. Hybrid silencers combine elements of conventional baffle designs with high flow rate geometries such as those implemented in HUXWRX Flow-Through technologies, and others.
Like the 30 caliber Trident Ti, the smaller 5.56 mm Off Grid Operator Ti possesses a ported conventional cone blast baffle which feeds a relatively complex toroidal spiral internal structure, terminating with additional distal vents. In contrast to Flow-Through technologies, the blast propagation from the distal end of a silencer possessing a hybrid technology may possess different characteristics, even if it possesses distal venting ancillary to the bore. In a gross sense, this is due to a lower flow rate facilitated by early time blast load reflections and subsequent stagnation.
It is interesting to compare the performance of silencers in this size class (less than 6.6 inches long), on the standard 5.56 MK18 weapon system. In addition to the the CAT WB, competitors include the CGS SCI-SIX, Surefire SOCOM556-RC2, Liberty Precision Machine Torch, Otter Creek Labs Polonium, and PWS BDE 556. Of those competitors, the CAT WB is the smallest and most balanced, with the the SCI-SIX and Torch also providing a somewhat balanced balanced net result on the weapon system. The RC2, Polonium, and BDE systems possess higher back pressure, as discussed in the referenced testing and analysis reports.
In the tested Ti configuration, the Operator Ti weighs only 8.4 ounces. The titanium version of the CAT WB is lighter, and there are no other models in the research pedigree in this size class with a weight in that range. The 5.8-inch long Energetic Armament ARX weighs 8.8 ounces in the tested configuration, but its suppression performance is significantly lower on this weapon system, relative to other silencers in the Standard.
Like the Off Grid Suppressors Trident Ti, the Operator Ti is a direct-thread-only model. If the user wishes to adapt the silencer to firearms possessing a different thread diameter and pitch than 1/2-28tpi, thread adapters may be used. Significant caution is urged for the use of such adapters, as bore concentricity and other dimensional variations may significantly influence system operation.
The silencer is also offered in an Inconel model; users requiring increased durability for aggressive firing schedules may find this attractive. PEW Science has not performed durability testing or evaluation of Off Grid silencers. The user is encouraged to contact the manufacturer for use guidance.
In this review, the Off Grid Suppressors Operator Ti 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.
