SSS.6.236 - FOR Systems MK12 Mod FOR and the M4A1 Mid-Gas 5.56x45mm 14.5-in Barrel Automatic AR15 Rifle (Free Version)
/FOR Systems MK12 Mod FOR on the M4A1 Mid-Gas 5.56x45mm AR15 with 14.5-in Barrel
The MK12 Mod FOR is designed by Front of Rifle (FOR) Systems. It is a .264 caliber (6mm) centerfire reflex rifle silencer, intended to suppress the 5.56x45mm NATO cartridge on reciprocating weapons with barrel lengths of 14.5 inches and longer. It has a variable diameter increasing from 1.5-inch diameter at the proximal end to 1.62-in at the distal end. The length of the silencer body is 7.4 inches; the length increases to 7.84 inches when installed on a first-generation OCL OTB muzzle device adapter (duplicating the OPS INC thread and taper interface). When installed on the host weapon, the resulting silencer length from the barrel shoulder is approximately 5.6 inches. Therefore, that is the length recorded in the Silencer Sound Standard Rankings database. The entirety of the silencer is 3D-printed Grade 5 titanium. The MK12 Mod FOR weighs 11.2 ounces and the first-generation OCL OTB muzzle device weighs 2.5 ounces for a total system weight of 13.7 ounces, as tested. The MK12 Mod FOR can be obtained from Silencer Shop.
Silencer Hazard Map:
The predicted personnel hazards generated by the tested weapon systems in this report, in the free field, are shown in the adjacent Silencer Hazard Map. Click or tap the Map to enlarge. Please reference Silencer Hazard Map Brief 8.1.33 for further details. The PEW-SOFT HD Blast Hazard Prediction Tool and Hazard Mapper is presented in Report 8.1.1.
FOR Systems MK12 Mod FOR 14.5-in M4A1 AR-15 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
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-FOR-155-001-26. Therefore, data pertaining to the MK12 Mod FOR in this Sound Signature Review are published with the express written permission of DB Technologies, LLC.
The testing and analysis presented in this Sound Signature Review is of the FOR Systems MK12 Mod FOR on the M4A1 Mid-Gas Automatic AR-15 rifle, chambered in 5.56x45mm NATO with a 14.5-inch barrel. Federal XM193 55gr ammunition was used in the test. The standard PEW Science M4A1 test host weapon system is described in Public Research Supplement 6.127.
Report Table of Contents:
Section 6.236.1 contains an abbreviated overall summary of the FOR Systems MK12 Mod FOR rifle silencer performance on the 14.5-in M4, compared with the Top 5 silencers on this platform in the current Rankings.
Section 6.236.2 contains FOR Systems MK12 Mod FOR test results and analysis.
Section 6.236.3 contains overall Suppression Rating comparisons of the MK12 Mod FOR silencer with other rifle silencers on the current market on the M4A1 Mid-Gas Rifle, including various configurations of the Tuna Cans 5.56 XL, WRMFZY 5.56, CAT ST, Otter Creek Labs OCM5 and OCM6, Whiskey Quebec 5.56 Purged and Non-Purged, Wolfpack Armory Disruptor 556, Otter Creek Labs Infinity, Dillon DRC556, CAT TSWIF, Sylvan Arms SA223TIS, BOE Mod 1, Echo Zulu Defense X1R556-Ti, PTR VENT Spiritus 556i, HUXWRX FLOW 556 Ti, Surefire SOCOM556-MINI2, KAC QDC/CRS-PRT, KAC QDC/MCQ-PRT, CAT/WB/A1, and Surefire SOCOM556-RC2.
Section 6.236.4 contains an article summary and PEW Science laboratory staff opinions.
Summary: When paired with the 14.5-in barrel M4A1 and fired with Federal on an over-the-barrel mount, the FOR Systems MK12 Mod FOR achieved a Suppression Rating™ of 40.2 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.
6.236.1 FOR Systems MK12 Mod FOR Silencer Automatic Rifle Suppression Performance Summary
The PEW Science Silencer Sound Standard includes the 5.56x45mm NATO evaluation of many rifle silencers. Comprehensive performance Rankings are tabulated in Section 7 of the Standard. This report examines the performance of the FOR Systems MK12 Mod FOR reflex silencer on the standard untuned 14.5-in barrel M4A1 weapon system.
Figure 1 presents a gross performance comparison of the MK12 Mod FOR with the unsuppressed M4 rifle signature hazards, along with the Top 5 performing silencers on this platform from the current Rankings. The silencers are presented in order of mounted length past the barrel shoulder, from shortest to longest and the lengths are annotated in the figure.
Figure 1. Suppression Rating Comparisons of the FOR Systems MK12 Mod FOR with the Top 5 5.56 Rifle Silencers Using PEW-SOFT 5.56x45mm Supersonic M4A1 Test Data and PEW Science Analysis
The Top 5 performing silencers on the 5.56 M4 from the current performance Rankings shown in the above table, in order of mounted length past the barrel shoulder from shortest to longest, are the:
All of the above silencers (even arguably the Mod 1) are hybrid designs, in that they possess elements of both conventional and high flow rate silencers, coupled with other technology variations and staged elements to provide parametrically varied performance attributes. The MK12 Mod FOR is also a hybrid design, implementing technology with performance that is scalable with input pressure as demonstrated in their Monarch 7.62 with .308 (6.155), Monarch Recce with 5.56 (6.195), and Predator 6.5 with 6.5 PRC (6.228) silencers.
The following are gross conclusions from the above test data and analysis:
Notably, the MK12 Mod FOR produces competitive suppression performance with several of the Top 5 silencers on the M4 with a shorter effective length. Like the above mentioned Otter Creek Labs OCM 5 and the higher flow variant OCM 6 (6.213), the FOR Systems MK12 Mod FOR is a reflex design. This allows for length reduction past the barrel shoulder. Note the MK12 Mod FOR has lower back pressure than the OCM 5, and is lighter and shorter when using the same over-the-barrel mounting system.
Operator protection on an untuned M4 almost always suffers without system tuning. The rifle is over-gassed for reliability purposes, purposely by the manufacturer. This is the case with many stock AR-15 rifles. Even purposefully high flow rate silencers like the Spiritus 556i produce operator Suppression Rating metrics in the mid 20s on this standard host.
Operator protection is not necessarily correlated with “gas to the face” on an AR-15 system. Back pressure in a silencer, which is a function of internal early- and late-time flow rates, influences the severity of both ejection port blast and late-time gaseous byproducts of combustion from the chamber and gas tube, escaping from the ejection port of the rifle. Blowback can vary based on the rifle system, ammunition, firing schedule, and mounting system, even with the same silencer. In the case of the silencers in the above chart, all possess varying flow rates, and some provide less “gas to the face” than others, despite the operator (shooter’s ear) Suppression Ratings being somewhat similar on this standardized host rifle. Again, as stated in (2), the rifle is over-gassed, which reduces the resolution of ejection port blast correlation with back pressure. As detailed in the raw shooter’s ear waveforms measured with the MK12 Mod FOR silencer in the test and documented in this report, some high flow rate (low back pressure) signs are visible. These should be viewed as supplementary indicators in the analysis. Similar low back pressure signs are present in the CAT/ST, Dillon DRC556, and PTR VENT Spiritus 556i evaluations, for example. Severe back pressure signs are present in the OCM 5 raw blast test data.
The detailed 5.56x45mm NATO 14.5-in M4A1 evaluations of the MK12 Mod FOR rifle silencer follows.
6.236.2 FOR Systems MK12 Mod FOR Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the FOR Systems MK12 Mod FOR 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. FOR Systems MK12 Mod FOR Sound Metric Summary
6.236.2.1 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 FOR Systems MK12 Mod FOR are shown in Figure 2a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 2b, in early time. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 3a. In Figure 3b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shots 2 and 3.
Fig 2a. FOR Systems MK12 Mod FOR 5.56x45mm NATO M4A1 Automatic Rifle Muzzle Sound Pressure Signature
Fig 2b. FOR Systems MK12 Mod FOR 5.56x45mm NATO M4A1 Automatic Rifle Sound Pressure Signature
Figure 3a. FOR Systems MK12 Mod FOR 5.56x45mm NATO M4A1 Automatic Rifle Muzzle Sound Impulse Signature
Figure 3b. FOR Systems MK12 Mod FOR 5.56x45mm NATO M4A1 Automatic Rifle Muzzle Sound Impulse Signature
As described in the report introduction, the Front of Rifle Systems MK12 Mod FOR is a hybrid design in a reflex configuration. For an overview of the three primary classes of rifle silencer designs, the reader is encouraged to review PEW Science Research Supplement 6.169. With only 5.6 inches of length past the barrel shoulder with OCL the over-the-barrel mount, it produces very competitive suppression performance on the 14.5-in M4 AR-15.
The technology used in the MK12 Mod FOR, including its first reflector (blast baffle) is based on the design present in the FOR Monarch Recce (6.195) with elements of the FOR Predator 6.5 (6.228) in later stages. It is very important to note that the MK12 Mod FOR does possess an engineered reflex section, in contrast with some reflex silencers that possess unoccupied featureless reflex volumes (e.g. OCM 5 and others). The actual functional utilization of reflex silencer volumes is a topic of continued research and is not in the scope of this report.
PEW Science Research Note 1: The above raw blast overpressure and impulse data measured in the test of the MK12 Mod FOR displays the following:
Moderate peak blast overpressure with moderate blowdown duration. Bolt carrier group (BCG) return to battery timing is somewhat typical for low back pressure silencers on this weapon system (Fig. 2a).
Initial precursor flow is very consistent, along with initial coupled jetting, from shot to shot. First-round-pop (FRP) divergence happens very early and almost immediately as jetting begins (Fig. 2b).
Initial blast impulse accumulation is relatively expedient. Impulse accumulation takes some time to stabilize as the shot string continues (Fig. 3a).
Momentum is throttled after the primary accumulation phase, in all shots (Fig. 3).
Observations (1) and (3) are congruent with reduced back pressure silencer behavior and the behavior in (2) is somewhat consequential. Observation (4) may be a function of the added reflex volume and late blowdown delay. Note that there is a distal vent array in the MK12 Mod FOR and this contributes to the behavior in (3).
PEW Science Research Note 2: The FRP quench that occurs in the middle of the impulse plateau shows the event to be short-lived; relative signature severity in the first shot is somewhat masked to operators and bystanders, in accordance with PEW Science analysis. General consistency from the silencer is not as robust as some non-reflex designs. This may be a function of the implementation of the distal vent array. Nonetheless, overall suppression performance is strong and highly competitive, especially for the effective length and overall weight. There are five other silencer configurations in the research with effective lengths less than or equal to 5.6 inches:
The MK12 Mod FOR significantly outperforms those silencers in gross signature suppression with a minimal overall effective increase in length on the host rifle. This is a very notable practical performance achievement. It is important to note that the KAC MCQ silencer exhibits a muzzle Suppression Rating less than 20 on this host; two full performance categories lower than that of the MK12 Mod FOR. This is a nontrivial and highly significant performance differential. The MCQ is effectively an inch shorter, but the extreme performance loss may not be worth that length decrease to many end users.
Also as previously stated, the MK12 Mod FOR outperforms the Otter Creek Labs OCM 5 (6.213) in suppression performance and back pressure reduction, in a shorter and lighter design envelope. This achievement is notable. The MK12 Mod FOR also outperforms the lower back pressure variant Otter Creek Labs OCM 6 (6.213).
PEW Science Research Note 3: 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 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 90 ms in Figure 2a) 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 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 may be 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 entire signatures are used in analysis and Suppression Rating calculations.
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 Front of Rifle Systems MK12 Mod FOR is 40.1 and the at-ear Suppression Rating is 19.4; considerably different zones on the Suppression Rating Dose Chart. The “over gassed” nature of the rifle contributes to severe ejection port blast signature on the standard untuned M4A1 weapon system. System tuning (adjustable gas block or heavier buffer mass) may be required to optimize the user’s particular 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 with the MK12 Mod FOR are presented and analyzed in the full Member Version of this report.
Comparison with the rest of the silencers in the M4 Rankings follows.
6.236.3 Suppression Rating Comparison (5.56x45mm from the M4A1)
Figure 6 presents a comparison of the PEW Science Suppression Ratings of the MK12 Mod FOR rifle silencer with those of several other silencers on the M4A1 weapon system. The standard PEW Science M4A1 test host weapon system is described in Public Research Supplement 6.127. As in Figure 1, the silencers are presented in order of mounted length past the barrel shoulder, from shortest to longest.
Figure 6. Suppression Rating Comparisons of the FOR Systems MK12 Mod FOR, Tuna Cans 5.56 XL, WRMFZY 5.56, CAT ST, Otter Creek Labs OCM5, OCM6, Whiskey Quebec 5.56 Purged and Non-Purged, Wolfpack Armory Disruptor 556, Infinity, Dillon DRC556, CAT TSWIF, Sylvan Arms SA223TIS, BOE Mod 1, Echo Zulu Defense X1R556-Ti, PTR VENT Spiritus 556i, HUXWRX FLOW 556 Ti, KAC QDC/CRS-PRT, KAC QDC/MCQ-PRT, Surefire SOCOM556-MINI2, CAT WB, and SOCOM556-RC2 with different mounts, Using PEW-SOFT 5.56x45mm Supersonic Test Data and PEW Science Analysis
Figure 6 presents an overall summary of the postulated hazards to the operator and bystanders when fielding the FOR Systems MK12 Mod FOR on the M4A1 weapon system (shown in red). Data is also presented for the fielding cases of the Tuna Cans 12-baffle 5.56 XL and WRMFZY 5.56 (6.229), CAT ST (6.217), Otter Creek Labs OCM5 and OCM6 (6.213), Battle Born Supply Co. Whiskey Quebec 5.56 series (6.206), Wolfpack Armory Disruptor 5.56 (6.199), Otter Creek Labs Infinity (6.196), Dillon DRC556 (6.194), CAT TSWIF (6.193), Sylvan Arms SA223TIS (6.187), BOE Mod 1 (6.183), Echo Zulu Defense X1R556-Ti (6.181), PTR VENT Spiritus 556i (6.176), HUXWRX FLOW 556 Ti (6.168), Surefire SOCOM556-RC2 (6.128), SOCOM556-MINI2 (6.144), and KAC QDC PRT units (6.156) on different muzzle devices, along with fielding of the CAT WB (6.130). 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. 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.
Bystander Protection: Free field blast hazards adjacent to the weapon system are compared below:
The FOR Systems MK12 Mod FOR produces a 40.1 muzzle (bystander) Suppression Rating on this system. Therefore, it produces free field bystander hazard reduction on par with the following silencers on the standard 14.5-in M4 weapon system:
Operator Protection: Free field blast hazards to which the operator is subjected are compared below:
The FOR Systems MK12 Mod FOR produces a 19.4 shooter’s ear (operator) Suppression Rating on this system. Its standard untuned M4 free field operator protection is on par with that of the:
It is important to note that outside of the free field, the above silencer configurations will exhibit differing operator protection. For example, a MK12 Mod FOR and a CAT ST would protect the operator much more than a KAC 556 QDC/MCQ-PRT in enclosed spaces due to additive blast overpressure reflections from severe muzzle blast from the KAC silencer. The reader may examine this phenomenon visually in the case study presented in Section 8.1.1.5 of the Standard: Surefire SOCOM556-RC2 vs. HUXWRX FLOW 556k Hazard Maps (Reflections) in the initial PEW-SOFT HD methodology report here.
As previously discussed in Research Note 2, the MK12 Mod FOR significantly outperforms some short silencers in gross signature suppression with a minimal overall effective increase in length on the host rifle. This is a very notable practical performance achievement. It is important to note that the KAC MCQ silencer exhibits a muzzle Suppression Rating less than 20 on this host; two full performance categories lower than that of the MK12 Mod FOR. This is a nontrivial and highly significant performance differential. The MCQ is effectively an inch shorter, but the extreme performance loss may not be worth that length decrease to many end users. Also as previously stated, the MK12 Mod FOR outperforms the Otter Creek Labs OCM 5 (6.213) in suppression performance and back pressure reduction, in a shorter and lighter design envelope. This achievement is notable. The MK12 Mod FOR also outperforms the lower back pressure variant Otter Creek Labs OCM 6 (6.213).
PEW Science Research Note 8: Reflex silencer designs take advantage of otherwise unoccupied area aft of the barrel muzzle to increase potential volumetric expansion of combustion gasses in the hopes of increasing suppression performance. While it is true that increased volume can be gained by such designs, the effective utilization of that volume has historically posed a challenge for silencer designers. As additive manufacturing continues to enable designers to create innovative silencer products, reflex designs may see increased performance efficacy. At the current time, with supersonic 5.56 NATO rifle suppression, current research demonstrates that they may not always reach their full potential when compared to flush-mounted muzzle silencers of similar total size. Research is ongoing.
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.
6.236.4 Review Summary: FOR Systems MK12 Mod FOR on the M4A1 Mid-Gas 5.56x45mm AR15 with 14.5-in Barrel
When paired with the 14.5-in barrel M4A1 and fired with Federal on an over-the-barrel mount, the FOR Systems MK12 Mod FOR achieved a Suppression Rating™ of 40.2 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 Front of Rifle Systems MK12 Mod FOR is a 6mm reflex rifle silencer that produces competitive 5.56 NATO suppression performance on the standard M4 rifle with a shorter effective length than many silencers. Additionally, due to being constructed from 3D printed titanium, the MK12 Mod FOR is lighter than many competing models. The silencer uses similar technology found in the FOR Monarch Recce and Predator 6.5 silencers, in a reflex configuration that fits back over the user’s barrel using any mounting solution compatible with the OPS INC MK12 thread and taper interface used for the legacy OPS INC 12th Model silencer originally designed by Phil Seberger and Manufactured by Ron Allen, now seen in the Allen Engineering AEM5. Users installing reflex silencers must remain mindful of available space on their exposed gun barrel to avoid interference with rails and accessories.
The technology used in the MK12 Mod FOR, including its first reflector (blast baffle) is based on the design present in the FOR Monarch Recce with elements of the FOR Predator 6.5 in later stages. It is very important to note that the MK12 Mod FOR does possess an engineered reflex section, in contrast with some reflex silencers that possess unoccupied featureless reflex volumes (e.g. OCM 5 and others).
The MK12 Mod FOR significantly outperforms short silencers like the Surefire SOCOM556-MINI2, CAT/TSWIF, and KAC 556 QDC/MCQ-PRT in gross signature suppression with a minimal overall effective increase in length on the host rifle. As the effective length of the MK12 Mod FOR is approximately 5.6 inches forward of the barrel shoulder, this is a very notable practical performance achievement. It is important to note that the KAC MCQ silencer exhibits a muzzle Suppression Rating less than 20 on this host; two full performance categories lower than that of the MK12 Mod FOR. This is a nontrivial and highly significant performance differential. The MCQ is effectively an inch shorter, but the extreme performance loss may not be worth that length decrease to many end users. The MK12 Mod FOR also outperforms the Otter Creek Labs OCM 5 in suppression performance and back pressure reduction, in a shorter and lighter design envelope. This achievement is notable. The MK12 Mod FOR also outperforms the lower back pressure variant Otter Creek Labs OCM 6.
The Otter Creek Labs over-the-barrel (OTB) mounting system used in this test of the FOR Systems silencer is extremely simple to use; it may be installed onto a standard AR-15 rifle barrel and the included rear taper interfaces with the MK12 Mod FOR as well as with legacy OPS INC models, providing expedient adaptability of this family of reflex silencers to existing weapon systems that would otherwise require barrel modification. The user is encouraged to exercise due diligence when planning to install reflex silencers on host weapons as AR-system handguards and other accessories, such as gas blocks, may interfere. For example, this test program required removing the Daniel Defense handguard from the standard M4A1RIII test host to facilitate installation of the silencer test specimen. Users are encouraged to contact the silencer manufacturer for exact system component dimensions.
The MK12 Mod FOR does possess some low back pressure features. Note that the standard untuned M4 test host is relatively “over-gassed” and the flow rate features of the silencer are not showcased by the shooter’s ear Suppression Rating, alone, as discussed in the full version of this report.
In this review, the FOR Systems MK12 Mod FOR 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.
