SSS.6.155 - FOR Systems Monarch 7.62 and the Savage Model 10 PC .308
/FOR Systems Monarch 7.62 on a Savage Model 10 .308 with 20-in Barrel
The Monarch 7.62 is designed by Front of Rifle Systems (FOR Systems). It is a 30 caliber centerfire rifle silencer, intended to suppress many cartridges with projectiles appropriately sized to travel through the bore. It has a 1.75-inch diameter and is 6.4 inches in length, without a mount. The user may choose to install third-party adapters compatible with the 1.375”-24tpi system. The total length with the tested mount and flash hider is 7.1 inches. The silencer is manufactured from 718 Inconel alloy by DMLS (3D printing). As tested, the silencer weighs 20 ounces and the mount and flash hider weigh 3.6 ounces, for a total tested system weight of 23.6 ounces. The Monarch 7.62 can be obtained from FOR Systems Dealers.
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 data production for this Sound Signature Review was funded in part by PEW Science Project PEW-FOR-078-001-24. Therefore, data pertaining to the Monarch 7.62 in this Sound Signature Review is published with the express written permission of DB Technologies, LLC.
This review contains single test results using the Monarch 7.62 with a Rearden ATLAS mounted to a Liberty Precision Machine Eclipse flash hider 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 6.155.1 contains the Monarch 7.62 test results and analysis.
- Section 6.155.2 contains back pressure and Suppression Rating comparisons with selected .30 rifle silencers possessing a PEW Science Back Pressure Metric, Ω [Pa-1] in Omega Zone 5 and below. An updated Ω metric chart for the full suite of publicly evaluated .30 rifle silencers is also provided in this section. Further information about the Ω metric and Omega Zones can be obtained in PEW Science Research Supplement 6.40 (Public Article).
- Section 6.155.3 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 FOR Systems Monarch 7.62 with with a Rearden ATLAS mounted to a Liberty Precision Machine Eclipse flash hider achieved a Suppression Rating™ of 44.9 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
6.155.1 FOR Systems Monarch 7.62 Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Monarch 7.62 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. FOR Systems Monarch 7.62 Sound Metric Summary
6.155.1.1 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 Monarch 7.62 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 the first three shots.
Fig 1a. FOR Systems Monarch 7.62 Bolt Action Rifle Muzzle Sound Pressure Signature
Fig 1b. FOR Systems Monarch 7.62 Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window
Figure 2a. FOR Systems Monarch 7.62 Bolt Action Rifle Muzzle Sound Impulse Signature
Figure 2b. FOR Systems Monarch 7.62 Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window
Figure 1b shows a 1.2 millisecond long portion of the sound pressure signatures of the first three rounds fired from the FOR Systems Monarch 7.62, as measured 1.0 m left of the muzzle. There are several significant waveform features labeled:
Internal combustion within the silencer is relatively consistent and reaches a peak of 116.5 dB.
The end cap exit event, consisting of bullet shock and the initial jet, results in a peak overpressure magnitude of 142.3 dB.
Primary first-round-pop (FRP) jetting occurs early and continuously, diverging from normalized flow.
Peak pressure amplitudes occur during latent jetting.
This is a somewhat typical sequence observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer that exhibits relatively low to moderate flow restriction (back pressure). Internal silencer design can significantly influence the measured timing and pressure amplitudes. Preliminary back pressure comparisons are shown in Section 6.155.3 of this review, with the PEW Science Back Pressure Metric, Ω [Pa-1]. Note that weapon system influence is a function of both Ω and early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice. These factors include the PEW Science alpha parameter; a subject of internal research.
PEW Science Research Note 1: The FOR Monarch 7.62 possesses distal radial vents. The silencer also possesses interior vent structures beginning in the first proximal expansion (blast) chamber and progressing through the geometry. This combination of features are responsible for the relatively rapid rise to maximum positive phase impulse measured in the test, as displayed in Figure 2a. This results in the silencer being placed in Omega Zone 5 (ref. 6.40). Due to blast chamber venting, lowering the degree to which internal blast load impulse is able to accumulate near the muzzle orifice in early time, it is likely that the Monarch 7.62 influences semiautomatic weapon function less than some other silencers in the same Omega Zone. Further laboratory testing is needed.
PEW Science Research Note 2: The FRP from the Monarch 7.62 on this host weapon is relatively severe to bystanders immediately adjacent to the muzzle (see early divergence in Fig. 1a, and jet momentum accumulation with multiple rate changes in Fig. 2b). PEW Science analysis indicates the FRP from the Monarch 7.62 on this system to present to bystanders with approximately twice the severity as follow-up shots. This phenomenon is postulated to occur due to the progressive direct vent structures and exacerbated by the distal radial venting. It should be noted that muzzle pressure sensor locations are in-line with the silencer’s end cap; silencers with radial venting therefore present with lower muzzle Suppression Ratings due to pressure field shape and sensor location. As this is a bolt-action rifle test, the suppressed pressure field shape is also indicated from the shooter’s ear measurements and expressed in the calculated shooter’s ear Suppression Rating; the lack of weapon reciprocation and ancillary blast pressure sources allow for this variable isolation. When examining the pressure field near the shooter, there is shown to be a significant gradient. The shooter’s ear hazard level is significantly less severe than to personnel adjacent to the silencer on this weapon system. This is further discussed in the full Member Version of this report.
PEW Science Research Note 3: After FRP, the signature from the Monarch 7.62 significantly normalizes. It is not until Shot 5 in the string that system heating results in an additional rate of impulse accumulation (Fig. 2a). The relatively high flow rate of the Monarch 7.62 is partially responsible for this phenomenon. This also highlights a notable attribute of the silencer; out of its closest nearest competitors, its flow rate is significantly higher in some cases. The following silencers exhibit similar holistic sound field suppression performance, but with a higher degree of gross flow restriction:
The FOR Monarch 7.62 is able to provide a relatively high degree of shooter protection on this host weapon system, in the free field, and transfer external gas momentum at a rate placing it in Omega Zone 5. This is somewhat unusual. However, it is also important to note that the flow rate of the Monarch 7.62 does not approach that of silencers like the HUXWRX FLOW 762 Ti (6.113).
Interestingly, the Monarch 7.62 eclipses the performance of the similarly sized Diligent Defense Enticer S-Ti (6.68) in all metrics, while offering significantly lower back pressure. Although the Enticer S-Ti is titanium and lighter than the DMLS Inconel Monarch 7.62, a titanium version of the Monarch also exists. A similar comparison can be made with the Dead Air Nomad-Ti (6.44), and by postulation, with the Nomad Ti XC. The FOR Monarch 7.62 also outperforms much larger silencers on this host weapon system in hazard reduction, such as the Q Thunder Chicken (6.20). The Thunder Chicken also possesses significant back pressure, in both gross flow rate and shock-reflecting muzzle device (Q Cherry Bomb).
Consistent with the above measured pressure and impulse waveform features, the computed PEW Science Omega Metric is relatively low to moderate, placing the silencer in Omega Zone 5. Relative Suppression Rating and flow restriction (back pressure) data is presented in Section 6.155.2 of this review.
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.
6.155.1.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 5-shot test of the FOR Systems Monarch 7.62 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 5 shots are shown in Figure 3. The primary sound signature history is shown on the left. A zoomed-in timescale is displayed on the right, in the region of peak sound pressure for Shot 1, Shot 2, and Shot 3. The real sound impulse (momentum transfer potential) histories at the ear from the same 5-shot test are shown in Figure 4. Again, full and short timescales are shown.
Figure 3a. FOR Systems Monarch 7.62 Bolt Action Rifle Ear Sound Pressure Signature
Figure 3b. FOR Systems Monarch 7.62 Bolt Action Rifle Ear Sound Pressure Signature, Short Time Window
Figure 4a. FOR Systems Monarch 7.62 Bolt Action Rifle Ear Sound Impulse Signature
Figure 4b. FOR Systems Monarch 7.62 Bolt Action Rifle Ear Sound Impulse Signature, Short Time Window
Well away from the distal radial venting of the Monarch 7.62, the signatures measured at the shooter’s ear display some of the same phenomenology, albeit at significantly lower amplitude. For example, early time FRP divergence is still noted in pressure space (Fig. 3b), due to this being a muzzle-blast driven phenomenon, propagating to the shooter’s head. Similarly, the divergence results in increased gas momentum (Fig. 4b), as one would expect. Finally, the latent heating resulting in greater momentum accumulation during Shot 5 also presents to the shooter (Fig. 4a).
Despite all of the phenomena measured at the shooter’s position being congruent with that measured adjacent to the silencer at the muzzle, the shape of the pressure field and standoff created from the 20-in barrel results in a significantly safer environment for the weapon operator. During the first shot, the Monarch 7.62 may present as louder to the shooter. The system does not regain significant severity to the shooter until Shot 5.
PEW Science Research Note 4: The shooter’s ear protection from the Monarch 7.62 on this host is relatively unusual given the gross flow rate of the silencer. As the initial flow paths appear to be isolated from the primary collectors and bore, it is possible that a gas throttle results in enough time delay such that flow rate is maintained without more severe jetting. One supporting factor of this hypothesis is the slight decrease in momentum accumulation rate measured at the muzzle (beginning at approximately 30 ms in Figure 2 in the previous section). This rate decrease in all shots coincides with the easily visible FRP momentum rate change (exacerbated due to ancillary combustion propagation). Similar step changes are seen with some other silencers in this performance class.
As typical, the overall sound signature measured at the shooter’s ear possesses significantly less amplitude in both the pressure and impulse regimes than the signature measured at the muzzle (refer to Table 1). Furthermore, the application of both pressure and impulse at the shooter’s ear is delayed when compared to the pressure and impulse at the weapon muzzle. The combination of varying amplitude and rise time to peak amplitude influences the response of the human ear.
It is extremely important to note that muzzle signature influences the signature to the weapon operator. This is a test on a bolt-action rifle. Similar jetting phenomenon measured at the muzzle propagates toward the shooter. The standoff of the endcap to the shooter, as well as angle of incidence of the pressure (blast) waves, result in exponential decay of hearing damage risk when compared to personnel adjacent to the muzzle. Testing of the Monarch 7.62 on reciprocating systems is the subject of future PEW Science research.
6.155.2 Relative Suppression Rating and Back Pressure Comparisons (.30 Rifle Silencers)
The FOR Systems Monarch 7.62 suppressor is intended to offer significant sound signature suppression with lower flow restriction (back pressure) than similarly sized models. PEW Science has developed an empirical relation to quantify the back pressure (flow restriction) of silencers. Figure 5 and Figure 6 show supersonic suppression and back pressure 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. Please note the following:
The PEW Science Back Pressure Metric, Ω [Pa-1], may be generated for any silencer and suppressed weapon system using any suitable raw external overpressure signature data acquired 1.0 m left of the silencer end cap. PEW Science highly recommends data acquisition in accordance with The Silencer Sound Standard.
Omega Zones are presented in Table 3, below, which are intended to provide guidance to weapons developers, silencer designers, and end-users, with regard to flow restriction characteristics of different silencer designs. It is very important to note that silencers possessing a relatively high Ω can still provide functional use on weapon systems. Some weapon systems are more sensitive to Ω than others.
It is important to note that a silencer’s Omega Zone can shift when using a mounting scheme that differs from that used in the testing referenced in the published PEW Science Sound Signature Reviews. This phenomenon occurs due to some silencer mounting schemes significantly influencing flow restriction with some silencer designs.
The theoretical lower limit of flow restriction, or so-called "zero back pressure" would be represented by the unsupressed state, Ω = 0 [Pa-1].
PEW Science acknowledges that other dynamic events occur within a suppressed weapon system that can also influence weapon function. Therefore, PEW Science acknowledges that Ω is not the sole parameter one must consider for total supppressed weapon system operation. However, PEW Science postulates that the Ω metric influence can be significant. Note that weapon system influence is also a function of early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice. These factors include the PEW Science Alpha parameter; a subject of internal research.
The Back Pressure Metric relations are most easily viewed on a logarithmic scale (See Figure 6).
Figure 5. Omega Back Pressure Metric And Suppression Rating Comparisons Of .308 Rifle Silencers Using PEW-SOFT Data and Analysis
As stated above, the PEW Science Back Pressure Metric is most easily viewed on a logarithmic scale. The metric is nonlinear; the shape of the trend in the data presented in Figure 6, below, illustrates the potential thresholds of extreme flow rate (approaching the unsuppressed state) and extreme flow restriction (approaching the trapping of the maximum amount of combustion byproducts in a system).
Figure 6. Omega Back Pressure Metric Comparisons Of .308 Rifle Silencers Using PEW-SOFT Data and Analysis
Omega characterizes silencer back pressure. It is important to note that back pressure is not blow back. The back pressure of a silencer is the flow restriction it introduces in a suppressed weapon system. The blow back phenomenon that can occur during the use of a suppressed weapon system is caused by the reciprocating system actuating too early relative to overpressure decay within the weapon system, resulting in exposure of excessive internal system overpressure to atmosphere. Some weapons may be tuned to function well with silencers in a high Omega Zone. Some weapons may require low-Omega silencers due to constraints in their operating system(s). Omega metric technical details can be found in PEW Science Public Research Supplement 6.40.
Table 3. PEW Science Back Pressure Metric Omega Zones And Suppressed Weapon System Functional Descriptions
As stated above, weapon system influence is a function of both Ω and early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice. These factors include the so-called PEW Science Alpha parameter; a subject of internal research. The FOR Systems Monarch 7.62 was tested with a HUB adapter and flash hider which most likely does not significantly influence early time shock reflections near the muzzle, but more testing is needed to determine this influence. Mount geometry, chamber geometry, and the blast baffle shape all contribute to early-time flow restriction, in addition to late-time flow restriction characterized by Omega.
The FOR Systems Monarch 7.62 exhibits holistic performance on the weapon system that is relatively close to that of the CGS Helios QD, Solid Endcap (6.13). The Monarch 7.62 performs very similarly to the Liberty Precision Machine Anthem-S (6.79) and the Silencer Central Banish 30 Gold (6.69).
The Monarch 7.62 eclipses the performance of the similarly sized Diligent Defense Enticer S-Ti (6.68) in all metrics, while offering significantly lower back pressure. A similar comparison can be made with the Dead Air Nomad-Ti (6.44), and by postulation, with the Nomad Ti XC. The FOR Monarch 7.62 also outperforms much larger silencers on this host weapon system in hazard reduction, such as the Q Thunder Chicken (6.20).
Overall performance of the FOR Systems Monarch 7.62 on a .308 bolt-action rifle is bounded on the low end by lower performing systems such as the Dead Air Sandman-L (6.23). The performance is bounded on the high end by higher performing systems such as the Thunder Beast ULTRA 9 (6.24) and the Aero Precision Lahar-30L (6.112).
PEW Science urges the reader not to misconstrue a low Omega metric with the mirroring of unsuppressed weapon function, nor a high Omega Metric with absolute use prohibition on semi-automatic systems. Each weapon system may experience varying sensitivity to different Omega Zones and users may exhibit varying preference for weapon system function and operability. The Zones are provided by PEW Science to assist the reader with determination of postulated applicability of silencer types, as some users may only have experience with certain silencers. The Omega Metric is one performance indicator; it allows overall flow rate phenomena to be categorized independently from sound signature suppression performance. Note that weapon system influence is also a function of early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice.
It is extremely important to note that peak sound pressure [dB], peak sound impulse [dB-ms], and Omega (Ω) [Pa-1], alone, do not determine the sound supression performance of a silencer. It is the combination of these and other waveform parameters that form the total sound signature and the influence on human inner ear response. The PEW Science Suppression Rating computation considers all of these factors.
6.155.3 Review Summary: FOR Systems Monarch 7.62 on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80, the FOR Systems Monarch 7.62 with with a Rearden ATLAS mounted to a Liberty Precision Machine Eclipse flash hider achieved a Suppression Rating™ of 44.9 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 FOR Systems Monarch 7.62 is a mid-size 7.62mm rifle silencer that possesses extremely competitive sound signature suppression performance with somewhat lower back pressure than other designs in its class. The silencer is offered in two versions; DMLS (3D printed) Inconel alloy and Titanium. The Inconel version of the silencer is intended for heavy use on a variety of weapon systems.
The rear of the Monarch 7.62 is threaded for universal mount adaptation. The user may choose to install third-party adapters compatible with the 1.375”-24tpi system. No mount is included with the silencer.
The FOR Systems Monarch 7.62 exhibits holistic performance on the weapon system that is relatively close to that of the CGS Helios QD with its solid endcap, and the silencer also performs very similarly in gross suppression to the Liberty Precision Machine Anthem-S and the Silencer Central Banish 30 Gold, but does so with lower back pressure. The Monarch 7.62 eclipses the performance of the similarly sized Diligent Defense Enticer S-Ti in all metrics, while offering significantly lower back pressure. A similar comparison can be made with the Dead Air Nomad-Ti, and by postulation, with the Nomad Ti XC. The FOR Monarch 7.62 also outperforms much larger silencers on this host weapon system in hazard reduction, such as the Q Thunder Chicken (also a silencer with significantly higher back pressure).
Overall performance of the FOR Systems Monarch 7.62 on a .308 bolt-action rifle is bounded on the low end by lower performing systems such as the Dead Air Sandman-L. The performance is bounded on the high end by higher performing systems such as the Thunder Beast ULTRA 9 and the Aero Precision Lahar-30L.
It is postulated that the Inconel version of the Monarch 7.62 may be subjected to extreme firing schedules without damage. However, PEW Science has not subjected the Monarch 7.62 to severe automatic firing schedules and encourages the user to contact the manufacturer for guidance prior to use in such applications.
In this review, the Monarch 7.62 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.
