SSS.6.230 - Strategic Sciences MFMD + SDX and the Savage Model 10 PC .308 (Free Version)
/Strategic Sciences MFMD + SDX on a Savage Model 10 .308 with 20-in Barrel
The Multifunction Muzzle Device (MFMD) is designed by Strategic Sciences. Numerous variants of the system are available. The variant evaluated in this test program is the MFMD-7.62-3.0; a 30 caliber centerfire reflex (over the barrel) rifle silencer, intended to suppress many cartridges with projectiles appropriately sized to travel through the bore on both closed breech and reciprocating weapon systems, including on belt-fed machine guns with severe firing schedules. The system is modular and may be outfitted with two different length extension modules: the Suppressor Device (SD) and Suppressor Device Extended (SDX). The SDX 2.0-5.9 module was attached to the MFMD-7.62-3.0 in this test program.
The MFMD is 3D printed Inconel and has a somewhat rectangular cross section with a 2.74-in height and 1.84-in width. Its gross exterior length is 7.56 inches. The silencer is installed by direct-threading it to the barrel. Due to the 3-in reflex function (the MFMD occupies 3-in of barrel length aft of the barrel shoulder), the length of the MFMD forward of the barrel shoulder is 4.56 inches. With the SDX module installed, the total length of the system is 10.72 inches and the length forward of the barrel shoulder is 7.72 inches, as tested. The MFMD-7.62-3.0 weighs 26.4 ounces, and the SDX 2.0-5.9 module weighs 15.3 ounces, for a total system weight of 41.7 ounces, as tested.
This report examines the MFMD + SDX performance. MFMD performance without the SDX module installed was also evaluated by the PEW Science Laboratory and that test report publication is forthcoming. The MFMD may be obtained from Silencer Shop in different configurations, as well as directly from Strategic Sciences in the tested configuration.
Silencer Hazard Map:
The predicted personnel hazards generated by the tested weapon system 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 8.1.27 for further details. The PEW-SOFT HD Blast Hazard Prediction Tool and Hazard Mapper is presented in Report 8.1.1.
Strategic Sciences MFMD + SDX 20-in barrel .308 Bolt-Action 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-STRAT-156-001-26. Therefore, data pertaining to the MFMD in this Sound Signature Review is published with the express written permission of Strategic Sciences.
This review contains single test results using the Strategic Sciences MFMD + SDX on the Savage Model 10 Precision Carbine rifle, chambered in .308WIN with a 20-inch barrel. Federal XM80 149gr ammunition was used in the test.
Section 6.230.1 contains the Strategic Sciences MFMD + SDX test results and analysis.
Section 6.230.2 contains Suppression Rating comparisons with selected .30 rifle silencers in different length classes.
Section 6.230.3 contains the review summary and PEW Science laboratory staff technical opinions.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80, the Strategic Sciences MFMD + SDX achieved a Suppression Rating™ of 62.0 in PEW Science testing.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings.
6.230.1 Strategic Sciences MFMD + SDX Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Strategic Sciences MFMD + SDX 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. Strategic Sciences MFMD + SDX Sound Metric Summary
6.230.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories acquired with PEW-SOFT™ are shown below. 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 5 shots with the Strategic Sciences MFMD + SDX are shown in Figure 1a. The sound signatures of Shot 1, Shot 2, and Shot 3 are shown in Figure 1b, in early time. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 2a. In Figure 2b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2 and Shot 3.
Fig 1a. Strategic Sciences MFMD + SDX Bolt Action Rifle Muzzle Sound Pressure Signature
Fig 1b. Strategic Sciences MFMD + SDX Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window
Figure 2a. Strategic Sciences MFMD + SDX Bolt Action Rifle Muzzle Sound Impulse Signature
Figure 2b. Strategic Sciences MFMD + SDX Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window
The Strategic Sciences MFMD system is best described as a multi-stage next generation silencer. The MFMD system is advanced. In the PEW Science Silencer Sound Standard research taxonomy, the MFMD may be classified as having performance and design characteristics of hybrid designs. However, the MFMD is largely considered to be a next generation technology in that it does not possess any conventional silencer design features other than barrel threading, expansion chambers, and bore orifice. In fact, the only thing possessing geometry that resembles a traditional reflector (baffle) array in the Strategic Sciences system is the SDX module. And even then, the reflector elements in the SDX are combined with lateral cavities that, by definition, serve hybrid design functionality in their nature. From the moment of projectile uncorking and muzzle blast injection, spherical expansion and off-axis venting is facilitated. This is extremely important for reciprocating weapon system dynamics, as it results in an extremely low degree of early-time flow restriction; one of the primary drivers of system over function. On its own, the MFMD produces highly efficient signature suppression for its size, particularly in a reflex configuration. When outfitted with the SDX module, the distal vent arrays in the MFMD become input arrays for further reflection and expansion chambers. The SDX module actually possesses its own reflex portion that fits below the MFMD, further lengthening flow path geometry.
The Strategic Sciences MFMD system is intended to serve the following functions on several different types of weapon systems, in a compact length envelope:
Flash suppression.
Blast overpressure suppression (and thus “sound signature” suppression).
Recoil suppression.
Back pressure reduction, and thus ejection port blast reduction and cyclic rate reduction.
PEW Science Research Note 1: While the MFMD was explicitly developed to achieve the above four performance goals, all silencers achieve the first three goals, to at least some degree. By their very nature, all small arm weapon system silencers slow the introduction of expanding combustion gasses to atmosphere and therefore reduce the amplitude of flash in multiple spectra, reduce the amplitude and severity of blast overpressure propagation (also known as “sound signature suppression;” they are the same thing), and reduce system recoil. The mechanism by which most silencers reduce system recoil is by changing the amplitude and the interaction of distal thrust vectors with free air. In other words, through the same mechanisms required to suppress blast load propagation, the amplitude and timing of distal thrust vectors are reduced and modified such that they contribute less to system recoil. Again, these behavior modifications to a small arm weapon system by silencer use are inherent to the nature of signature suppression, in general.
Because the origination of recoil consists of two primary momentum components (projectile momentum and gas momentum), silencer recoil reduction through pure blast thrust propagation mitigation is most certainly limited. Other mechanisms may be used to further enhance the recoil reduction of a silencer:
Increased silencer mass.
Directional modification of the aforementioned suppressed external blast load thrust vectors.
The mechanism in (1) applies to not only silencers, but any weapon system component. Heavier guns recoil less than lighter guns, all other things equal. The mechanism in (2) is the same mechanism by which non-suppressing muzzle brakes function. Muzzle brakes direct blast load thrust vectors in directions that counteract recoil momentum. Therefore, for the mechanism in (2) to have high efficacy in silencer use, there must be enough distal blast momentum propagation, in the correct direction(s), to counteract recoil momentum. This is why silencer “muzzle brake end caps” are generally more effective with high pressure (magnum) rifle rounds. The MFDM does not use this mechanism to reduce recoil.
PEW Science Research Note 2: The above physical description of silencer function in Research Note 1 is paramount for the reader to understand, because the two primary mechanisms that enable the MFMD system to reduce recoil are its mass (1.18 kg as tested) and its low distal flow rate (high late-time back pressure), as quantified by a PEW Science Omega Metric of 1.11 [Pa^-1 x 10] from the measured free field blast impulse history shown in Figure 2a. A synonymous definition of low distal flow rate and high late-time back pressure is a high degree of distal momentum control.
Again, the MFMD does not use directional thrust vector modification for recoil reduction. However, there is a third mechanism by which the Strategic Sciences MFMD can reduce recoil, though it is not examined in this report. As mentioned above, the MFMD system also has high proximal flow rate (low early-time back pressure). As blast loads enter the silencer from the barrel muzzle, their reflections and subsequent internal impulse accumulation are reduced through complex geometry and vent arrays; load clearing off of the first internal reflectors is expedient, limiting the accumulation of impulse in early time. As a result of these early time internal blast load dynamics, reciprocating systems will undergo reduced recoil system velocity compared with some other silencers. Bolt carrier group (BCG) momentum is reduced. Momentum reduction in reciprocating mass in a small arm weapon system directly translates to lower perceived system recoil for the operator (the BCG impact into the end of the weapon’s receiver extension or “buffer tube,” for example, is less severe). Quantitative indicators of high early-time flow rate with the MFMD are present in the PEW Science evaluation of the 5.56 version of the MFMD system, which is forthcoming.
PEW Science Research Note 3: Much of the above described behavior is visible in the measured blast load histories from this test. The following are observations from the measured MFMD blast overpressure and impulse data:
Prolonged and low amplitude internal blast loads, as the muzzle blast propagates into the MFDM and then subsequently into the SDX module (Fig. 1a).
Low amplitude and controlled precursor flow, followed by distinct coupled jetting and subsequent low amplitude momentum egress (Fig. 1b).
Gradual jetting increase (both from the primary bore and top and bottom vent arrays of the SDX (Fig. 1b).
Low amplitude peak blast jet pressure (Fig. 1b) culminating in consistent and relatively low amplitude blast impulse (Fig. 2a).
Minimal first-round-pop (FRP) divergence in both pressure space (Fig. 1) and impulse space (Fig. 2) with highly controlled momentum ramp (Fig. 2a). This is further quantified by the aforementioned calculated Omega Metric of 1.11 [Pa^-1 x 10].
Observation (1) is a consequence of the unique design geometry and its physical length. Observations (2), (3), (4), and (5) illustrate the physical mechanisms by which the MFMD+SDX provides superior blast load (sound signature) suppression. When combined with the system weight, recoil reduction should be significant, based upon the blast momentum histories measured in this test. When further combined with high early-time flow rate, recoil reduction on reciprocating systems should be even more significant. Based on the above measured observations, it is likely that the MFMD system achieves its design goals, at least in spirit. This is an independent conclusion by the PEW Science laboratory and should not be taken as an endorsement of any conclusions reached by other laboratories that may also have independently evaluated this system, nor is it an endorsement of manufacturer performance claims. However, it is interesting to note that U.S. Government laboratory test results are congruent with those presented in this report.
The Silencer Hazard Map shown at the top of this report reflects the controlled nature of personnel blast hazards with the MFMD system.
PEW Science Research Note 4: The Strategic Sciences MFMD is available in both muzzle (flush) mount and over-the-barrel (OTB, or reflex) mount configurations. The tested MFMD-7.62-3.0 is a reflex unit that extends aft of the barrel shoulder by 3 inches. Detailed dimensions are provided at the top of this report. With the attached SDX module, as tested, the MFMD + SDX system mounted on the 20-in bolt-action rifle in this test program has an effective length of 7.72 inches. This is a notable metric, because not only does the MFMD system surpass the blast overpressure suppression performance of all other tested silencers in the research pedigree, it does so with significantly reduced effective length. The PTR VENT 1 (6.160) is the current flush (muzzle) mounted silencer performance leader, and has an effective tested system length of 9.1 inches, which is approximately 18 percent longer than the MFMD + SDX. Viewed another way, the MFMD + SDX is 15 percent shorter than the VENT 1. The pure blast load suppression performance of the MFMD is not extremely higher than that of the PTR VENT 1, but the fact it outperforms the VENT 1 in a shorter effective envelope and possesses much higher early-time flow rate, no doubt further increasing multiple performance metrics on reciprocating systems, is very notable.
This length class of 30 caliber rifle silencers represents an extremely competitive section of the market. As silencers reach and eclipse the 8-in total length threshold, performance begins to greatly increase. Note there are outliers (some shorter silencers provide exemplary performance) but this general rule holds true. The reader is encouraged to use the Suppression Rating Parametric Visualization Tool (Members Only) in the Rankings to filter by length and weight and view the competition spatially. In Section 6.230.2 of this report, the gross performance of two groups of silencers are compared with that of the Strategic Sciences MFMD + SDX; the Top 5 .308 bolt action silencers and all .308 bolt action silencers 8 inches in length and shorter. The top 5 silencers are, in order of length, ascending:
To illustrate these comparisons further, please see Figure 5 and Figure 6 in Section 6.230.2 of this report.
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 has made a concerted effort to characterize the FRP phenomenon with true physiological human inner-ear response analyses. Additional PEW Science Member Research Supplements containing this information are released periodically.
The Strategic Sciences MFMD + SDX shooter’s ear suppression performance is examined in the full Member Version of this report.
Overall performance comparisons are provided below.
6.230.2 Relative Suppression Rating and Length Comparisons (.30 Rifle Silencers)
The Strategic Sciences MFMD + SDX suppressor is intended to offer high sound signature suppression across the pressure field, in a very compact length.
Figure 5 and Figure 6 show supersonic suppression comparisons between selected 7.62mm (30 caliber) rifle silencers shown in public PEW Science Sound Signature Reviews, as of the date of this review publication. The results shown in Figure 5 and Figure 6 are calculated from real test data acquired with PEW-SOFT.
Figure 5 presents a performance comparison of the Strategic Sciences MFMD + SDX with the Top 5 tested silencers on this weapon system. Figure 6 presents a performance comparison of the Strategic Sciences MFMD + SDX with silencers greater than or equal to 8 inches long. The presented length metrics are inclusive of mount, forward of the barrel shoulder, as tested.
The figures present the silencers in order of the aforementioned total measured and tested system lengths.
Figure 5. Suppression Rating and Length Comparisons Of the Strategic Sciences MFMD + SDX and the Top 5 .308 Rifle Silencers Using PEW-SOFT Data and Analysis
Figure 6. Suppression Rating and Length Comparisons Of .308 Rifle Silencers greater Than or equal to 8 inches long Using PEW-SOFT Data and Analysis
Note that the above 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.
As previously stated, with the attached SDX module, the MFMD + SDX system mounted on the 20-in bolt-action rifle in this test program has an effective length of 7.72 inches. This is a notable metric, because not only does the MFMD system surpass the blast overpressure suppression performance of all other tested silencers in the research pedigree, it does so with significantly reduced effective length.
The top 5 silencers are, in order of length, ascending:
The Strategic Sciences MFMD + SDX outperforms all of the above silencers in blast overpressure mitigation. The PTR VENT 1 (6.160) is the current flush (muzzle) mounted silencer performance leader, and has an effective tested system length of 9.1 inches, which is approximately 18 percent longer than the MFMD + SDX. Viewed another way, the MFMD + SDX is 15 percent shorter than the VENT 1. It is likely that the Strategic Sciences MFMD + SDX also outperforms the above silencers in early time system backpressure reduction. This hypothesis is based on other PEW Science Laboratory testing of the 5.56 version(s) of the MFMD system on the 14.5-in M4A1RIII AR-15 (publication forthcoming).
There is most likely no other silencer system, tested to date, that combines the level of pure blast overpressure (sound signature) suppression performance with back pressure reduction and recoil reduction of the MFMD system, for the length. The system weight and flow dynamics dictate significant recoil reduction potential.
PEW Science Research Note 6: To put the performance of this system in perspective, the effective length of the Strategic Sciences MFMD + SDX is a tenth of an inch longer than the Aero Precision Lahar-30L (6.112). The muzzle and ear Suppression Ratings of the two systems are two performance categories apart. The human risk, from blast overpressure, of operating the weapon system equipped with a traditional silencer like the Lahar-30L versus the next generation MFMD is starkly different. Additive manufacturing does not, by itself, result in advanced silencer performance. It is the design ideas brought to life by additive manufacturing that result in systems like the MFMD. The future of suppressed small arms technology is bright.
The user is encouraged to be mindful of the degree to which sound signature suppression, and resulting personnel hazards, can vary across designs. 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.
6.230.3 Review Summary: Strategic Sciences MFMD + SDX on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80, the Strategic Sciences MFMD + SDX achieved a Suppression Rating™ of 62.0 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 Strategic Sciences Multifunction Muzzle Device (MFMD) is a next generation rifle silencer. Its combined performance attributes and effective length result in a highly competitive system optimized for a variety of different small arm weapon systems. When the SDX extended suppression module is added to the end of the MFMD, the silencer has an effective length of 7.7 inches and outperforms every tested silencer in the research in blast overpressure suppression, to date. The high early time flow rate, controlled blast propagation, and recoil control of the MFMD are all strong performance traits. The system is also relatively heavy. Users should consider system weight when determining application suitability. Note that the system weight is one consequence of the extreme durability requirements of the MFMD design. The silencer may be used on belt-fed machine guns.
The Strategic Sciences MFMD system is best described as a multi-stage next generation silencer. The MFMD system is advanced. In the PEW Science Silencer Sound Standard research taxonomy, the MFMD may be classified as having performance and design characteristics of hybrid designs. However, the MFMD is largely considered to be a next generation technology in that it does not possess any conventional silencer design features other than barrel threading, expansion chambers, and bore orifice. In fact, the only thing possessing geometry that resembles a traditional reflector (baffle) array in the Strategic Sciences system is the SDX module. And even then, the reflector elements in the SDX are combined with lateral cavities that, by definition, serve hybrid design functionality in their nature. From the moment of projectile uncorking and muzzle blast injection, spherical expansion and off-axis venting is facilitated. This is extremely important for reciprocating weapon system dynamics, as it results in an extremely low degree of early-time flow restriction; one of the primary drivers of system over function. On its own, the MFMD produces highly efficient signature suppression for its size, particularly in a reflex configuration. When outfitted with the SDX module, the distal vent arrays in the MFMD become input arrays for further reflection and expansion chambers. The SDX module actually possesses its own reflex portion that fits below the MFMD, further lengthening flow path geometry.
The MFMD system has high proximal flow rate (low early-time back pressure). As blast loads enter the silencer from the barrel muzzle, their reflections and subsequent internal impulse accumulation are reduced through complex geometry and vent arrays; load clearing off of the first internal reflectors is expedient, limiting the accumulation of impulse in early time. As a result of these early time internal blast load dynamics, reciprocating systems will undergo reduced recoil system velocity compared with some other silencers. Bolt carrier group (BCG) momentum is reduced. Momentum reduction in reciprocating mass in a small arm weapon system directly translates to lower perceived system recoil for the operator (the BCG impact into the end of the weapon’s receiver extension or “buffer tube,” for example, is less severe). Quantitative indicators of high early-time flow rate with the MFMD are present in the PEW Science evaluation of the 5.56 version of the MFMD system, which is forthcoming.
The Strategic Sciences MFMD is available in both muzzle (flush) mount and over-the-barrel (OTB, or reflex) mount configurations. The tested MFMD-7.62-3.0 is a reflex unit that extends aft of the barrel shoulder by 3 inches. Detailed dimensions are provided at the top of this report. With the attached SDX module, as tested, the MFMD + SDX system mounted on the 20-in bolt-action rifle in this test program has an effective length of 7.72 inches. This is a notable metric, because not only does the MFMD system surpass the blast overpressure suppression performance of all other tested silencers in the research pedigree, it does so with significantly reduced effective length. The PTR VENT 1 is the current flush (muzzle) mounted silencer performance leader, and has an effective tested system length of 9.1 inches, which is approximately 18 percent longer than the MFMD + SDX. Viewed another way, the MFMD + SDX is 15 percent shorter than the VENT 1. The pure blast load suppression performance of the MFMD is not extremely higher than that of the PTR VENT 1, but the fact it outperforms the VENT 1 in a shorter effective envelope and possesses much higher early-time flow rate, no doubt further increasing multiple performance metrics on reciprocating systems, is very notable.
There exist multiple versions and configurations of the MFMD system for multiple weapon system types. The user may field the MFMD on everything from personal defense weapons to belt-fed magnum machine guns, to antimateriel rifles. The system may be subjected to heavy automatic fire. The system is heavy, but it should be noted that requisite durability under extreme firing schedules on the aforementioned weapon systems has significant material demand.
To install the MFMD system, barrel shims of multiple thicknesses (for timing) are included with the kit, along with a custom open-ended crows foot wrench attachment to apply proper torque. Written system instructions included for installation are relatively straightforward.
To install the SD an SDX modules on the end of an installed MFMD, the user simply hooks the attachment point in place, cams the module onto the MFMD, and actuates the retention lever until retention is achieved. To remove the module(s), the rear of a 5.56 NATO casing, or similar, is used to actuate the rear retention lever while simultaneously depressing the forward lever. Once learned by the weapon operator, it is a very simple operating mechanism. Laboratory staff did not encounter any issues in system or extension module installation on the test host weapon platforms during this test program.
In this review, the Strategic Sciences MFMD + SDX performance metrics depend upon suppressing a supersonic centerfire rifle cartridge; no easy 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 .308WIN cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact.
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.
