SSS.6.47 - Griffin Armament Optimus and the Savage Model 10 PC .308 (Free Version)

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Griffin Armament Optimus (Gen 2) on a Savage Model 10 .308 with 20-in Barrel

The Optimus is designed and manufactured by Griffin Armament. It is a multi-caliber centerfire silencer, possessing a 9mm bore in its primary baffles, intended to suppress centerfire rifle (up to and including 300 Winchester Magnum), centerfire pistol (up to and including 9mm), and rimfire. It has a 1.375-inch diameter and is 9.4 inches in length with the full-length taper mount adapter, called a blast shield attachment. The blast shield attachment allows the use of proprietary Griffin Armament taper mounts. This is referred to as the Full Size configuration, which weighs 17.8 ounces, without a taper mount. The silencer tube is constructed of 17-4 stainless steel, as are the Gen 2 ECO-FLOW baffles. The silencer was tested with the two-port taper mount Paladin brake. The full length blast shield is no longer offered by Griffin Armament; therefore, the Suppression Rating shown in this review is postulated to be lower with new Optimus silencers on this weapon system (see Version Notes, below). The Optimus can be obtained from Silencer Shop.

The configurations of the Optimus are numerous. The blast shield may be replaced with a minimalist blast shield, resulting in a 7.9-inch length and mandatory use of minimalist taper mounts. This is referred to as the Mid Size configuration, which weighs 15.7 ounces. The use of a blast shield may be omitted, and the silencer may instead be mounted with a variety of other muzzle devices including 3-lug, tilting barrel inertial decoupler pistons, and an A2 Griffin Armament Gate-LOK system. The weights and lengths of these configurations vary. The user is encouraged to contact the manufacturer for the latest system specifications.

Optimus Version Notes: The Optimus was originally released in 2016. During its product life, Griffin Armament has implemented successive manufacturing and performance improvements to the silencer’s design. The Optimus evaluated in this Sound Signature Review incorporates all of the internal improvements known to PEW Science, as of the date of this test report publication and is classified Gen 2, as released in 2020. However, PEW Science has been informed by Griffin Armament that at the time of this review publication, only the minimalist blast shield attachment is offered with the Optimus. This is shorter than the blast shield attachment tested by PEW Science. Therefore, the data in this review can be considered by the reader to be an upper bound representation of Griffin Optimus performance on the tested weapon system, with regard to both sound suppression and flow restriction (back pressure) metrics.

PEW Science postulates that the use of the newly included minimalist blast shield may result in different Suppression Rating and Omega Metric performance. The potential reduction in Suppression Rating on this host weapon, with the newly offered minimalist blast shield, is a function of both the internal silencer dimensional change and the change in proximity of the silencer endcap to the shooter’s ear when firing the weapon. Future testing of the so-called minimalist configuration is planned.

This review contains single-test results using the Optimus mounted with the dual port tapered muzzle brake on the Savage Model 10 Precision Carbine rifle, chambered in .308WIN with a 20-inch barrel. Federal XM80C 149gr ammunition was used in the test. Only the Full Size configuration of the Optimus was evaluated by PEW Science (with the original long blast shield attachment) .

  • Section 6.47.1 contains the Optimus test results and analysis.
  • Section 6.47.2 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 4 and above. Further information about the Ω metric and Omega Zones can be obtained in PEW Science Research Supplement 6.40 (Public Article).
  • Section 6.47.3 contains the review summary and PEW Science opinions.

Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80, the Griffin Armament Optimus in the Full Size (9.4-in) configuration mounted with the dual port taper muzzle brake, achieved a Suppression Rating™ of 38.1 in PEW Science testing.

Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings

6.47.1 Griffin Armament Optimus Sound Signature Test Results

A summary of the principal Silencer Sound Standard performance metrics of the Optimus 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 PEW Science testing, research, and development with a membership, here. State-of-the-art firearm sound signature testing and research conducted by PEW Science is supported by readers like you.

 

Table 1. Griffin Armament Optimus Sound Metric Summary

 

6.47.1.1 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.

Figure 1 shows a 1.8 millisecond long portion of the first round sound pressure signature of the Optimus as measured 1.0 m left of the muzzle. There are three significant waveform features labeled:

  1. The endcap exit event results in an initial overpressure peak magnitude of 140.4 dB.

  2. The first primary jet builds to an amplitude of 146.1 dB.

  3. Peak FRP is measured to reached a maximum overpressure amplitude of 147.5 dB.

This is a somewhat typical sequence observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer that exhibits 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 6.47.2 of this review, with the PEW Science Back Pressure Metric, Ω [Pa-1].

Fig 1. Griffin Armament Optimus First Round Bolt Action Rifle Muzzle Sound Pressure Signature, 24-OCT-2020

The waveform shown in Figure 1 is very similar to the FRP signature of silencers exhibiting flow restriction (back pressure) in PEW Science Omega Zone 5, such as the Rugged Surge in its Short Configuration (Review 6.22), the SilencerCo Omega 300 (Review 6.10), and the Dead Air Nomad-30 (1st Gen) in Review 6.43. There is observed early onset negative phase, but it is not as extreme as with the Griffin Explorr EX3 (Review 6.36), which has a higher mass flow rate (lower back pressure) and tubeless Gen 1 ECO-FLOW baffle geometry. The impulse decay of the Optimus is typical for silencers in this flow regime.

The Optimus has a large bore for the tested cartridge in this review; as it is able to accommodate 9mm projectiles, its mass flow rate is higher for its length than would otherwise be expected for centerfire rifles silencers with similar baffle designs. In addition to the larger center orifice, the large porting close to the bore line contributes to this flow rate increase (back pressure reduction). This is further discussed in Section 6.47.2, with performance comparisons to other centerfire rifle silencers.

Closer views of the first peak of all shots (Fig 2a) and highest peak of the first shot (Fig 2b) are shown below. Figure 2a illustrates the consistency of the endcap exit event between all 5 shots during the test. The endcap exit signature consistency in both amplitude and wave shape, from shot to shot, is discernable as a result of the high sample rate and raw, unfiltered data stream from PEW-SOFT. Figure 2b shows points later in time during Shot 1 as the maximum sound pressure occurs from the primary combustion event. Note that the total timescale in Figure 2a is 0.35 milliseconds (350 microseconds) and the total timescale in Figure 2b is only 0.1 milliseconds (100 microseconds). PEW-SOFT provides a sampling point every microsecond and the individual data points are shown in Figure 2b to illustrate this.

Fig 2a. Griffin Armament Optimus Bolt Action Rifle Muzzle Sound Pressure Early-Time Peaks, 24-OCT-2020

Fig 2b. Griffin Armament Optimus Bolt Action Rifle Muzzle Sound Pressure Shot 1 Peak, 24-OCT-2020

The primary sound signature pressure histories for all 5 shots with the Optimus are shown in Figure 3a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 3b, in early time. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 4a. In Figure 4b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2.

Fig 3a. Griffin Armament Optimus Bolt Action Rifle Muzzle Sound Pressure Signature, 24-OCT-2020

Fig 3b. Griffin Armament Optimus Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window, 24-OCT-2020

Figure 4a. Griffin Armament Optimus Bolt Action Rifle Muzzle Sound Impulse Signature, 24-OCT-2020

Figure 4b. Griffin Armament Optimus Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window, 24-OCT-2020

The Griffin Optimus does exhibit perceptible first round pop (FRP) at the muzzle on this platform. The FRP phenomenon is observable in the pressure regime, and it evident upon examination of the impulse waveforms in Figure 4 in both rise time and amplitude. It is interesting to note that unlike the abrupt impulse decay and high degree of impulse oscillation measured from the Gen 1 ECO-FLOW Griffin Explorr EX3 (Review 6.36), the impulse waveforms produced from the Gen 2 ECO-FLOW Optimus have typical decay. The difference in impulse wave shapes between the two silencer models is postulated to be indicative of an improvement in flow continuity. PEW Science inner ear modeling indicates FRP will be perceptible to bystanders with the Griffin Optimus on this host weapon platform, but the shooter may be unable to notice the FRP. This is in stark contrast to the Explorr EX3, a silencer which induces significantly more inner ear response.

PEW Science Research Note: PEW Science has only evaluated two examples of Griffin Armament ECO-FLOW technology; the Explorr EX3 (Gen 1 ECO-FLOW) and the Optimus in this review (Gen 2 ECO-FLOW). Although the baffles in the two silencers are different diameters and geometries, the signature differences observed are postulated to be a result of generational changes and not necessarily geometric scaling. PEW Science postulates that the change in porting geometry in the Gen 2 baffle allows for greater uniformity in flow restriction; a change in mass flow rate behavior that influences the sound signature significantly in frequency and phase by preventing severe pulsing phenomenon observed in the Gen 1 measurements.

Although the silencers are different lengths, the Explorr and Optimus can still be compared; the overall, muzzle, and ear Suppression Ratings for silencers tested by PEW Science, to date, can be compared directly using the tool in Section 7 of the Silencer Sound Standard - PEW Science Rankings. Section 6.47.2 of this review presents a comparison of Suppression Rating and back pressure for silencers with a flow restriction above a certain threshold (Omega Zone 4). Comprehensive silencer back pressure comparisons for .30 rifle silencers are available in PEW Science Public Research Supplement 6.40.

The Griffin Optimus achieves a Suppression Rating on par with that of the SilencerCo Omega 300 (Review 6.10) and Surefire SOCOM762-RC2 (Review 6.26) on this host weapon system. The Optimus exhibits lower flow restriction (back pressure) than the SilencerCo Omega 300, but higher back pressure than the Surefire SOCOM762-RC2.

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.

6.47.2 Relative Suppression Rating and Back Pressure Comparisons (.30 Rifle Silencers)

The Griffin Optimus suppressor is intended to reduced flow restriction (back pressure) and maximize sound signature suppression for its design envelope when used in the Full Size configuration. PEW Science has developed an empirical relation to quantify the back pressure (flow restriction) of silencers. Figure 7 shows 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 7 are calculated from real test data acquired with PEW-SOFT. Please note the following:

  1. 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 endcap. PEW Science highly recommends data acquisition in accordance with The Silencer Sound Standard.
  1. Omega Zones are presented in Table 2, 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.
  1. 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.
  1. The theoretical lower limit of flow restriction, or so-called "zero back pressure" would be represented by the unsupressed state, Ω = 0 [Pa-1].
  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.

Figure 7. Omega Back Pressure Metric And Suppression Rating 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 to 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 2. PEW Science Back Pressure Metric Omega Zones And Suppressed Weapon System Functional Descriptions

Like the Griffin Explorr, that uses Gen 1 ECO-FLOW baffles, the Optimus exhibits low flow restriction (back pressure) with its Gen 2 ECO-FLOW baffles. As discussed above, the Griffin Optimus achieves a Suppression Rating on par with that of the SilencerCo Omega 300 (Review 6.10) and Surefire SOCOM762-RC2 (Review 6.26) on this host weapon system. The Optimus exhibits lower flow restriction (back pressure) than the SilencerCo Omega 300, but higher back pressure than the Surefire SOCOM762-RC2. Interestingly, the Rugged Surge in its Short Configuration (Review 6.22) possesses a similar Omega Metric to that of the Optimus, but the Optimus is significantly quieter; a full Suppression Rating category quieter 1.0 m left of the silencer endcap. This performance differential is significant. However, the Optimus is 9.4 inches long, whereas the short configuration of the Rugged Surge is only 7.5 inches long. The back pressure differential is postulated to be due to the baffle porting and bore size of the primary baffles in the Optimus.

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.

6.47.3 Review Summary: Griffin Armament Optimus on a Savage Model 10 .308 with 20-in Barrel

When paired with the Savage M10 20” .308 and fired with Federal XM80, the Griffin Armament Optimus in the Full Size (9.4-in) configuration mounted with the dual port taper muzzle brake, achieved a Suppression Rating™ of 38.1 in PEW Science testing.

PEW Science Subjective Opinion:

The Griffin Armament Optimus is a modular, multi-caliber, 9mm bore centerfire rifle silencer that exhibits notably lower back pressure for its long length, with competitive sound signature reduction in the supersonic flow regime. The Optimus has been refined since its 2016 release; users should note that the supersonic suppression and back pressure characteristics of the Optimus highlighted in this review represent upper bound performance of the Optimus silencer on this host weapon platform. Newer iterations of the Optimus with the shorter minimalist blast shield may posses a lower Suppression Rating than achieved by the silencer evaluated in this review.

The Optimus contains curved cone baffles that have large ports in close proximity to the bore line; these so-called Gen 2 ECO-FLOW baffles are similar to those in the Explorr series, albeit with slightly different geometry and port shape. The blast baffle possesses a traditional .30 silencer bore size, with the primary baffles allowing 9mm projectiles in the appropriate configuration. Functionally, the Optimus baffle design allows for a relatively high mass flow rate for the silencer’s length, resulting in back pressure reduction on par with that of the 1st-Generation Dead Air Nomad or a Rugged Surge in its short configuration. The back pressure reduction of such silencers is not extreme, but it is reduced when compared to many “full size” silencers on the market. The Optimus, in the tested 9.4-inch length configuration, should be considered full size.

It is interesting to note that the full size blast shield is no longer offered by Griffin Armament. With only the minimalist blast shield available, reducing the silencer’s overall length to 7.9 inches, PEW Science postulates that the sound suppression performance of the silencer will be reduced on this host weapon platform. This is the subject of future PEW Science testing.

The mounting options possessed by the Griffin Armament Optimus are staggering; centerfire rifle taper mounts, handgun use, rimfire, and A2 flash hider mounting are significantly different configurations. The adaptability of such a system is admirable. However, users should be aware of possible compromises made when adapting a single silencer to many weapon platforms. Such compromises include weight, durability, size, and possibly Suppression Rating. Future PEW Science testing of the Optimus is expected to highlight various performance factors.

In this review, the Optimus 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.