SSS.6.188 - Off Grid Suppressors Scorpius and the Beretta 21A (Free Version)

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Off Grid Suppressors Scorpius on a Beretta 21A Subcompact Semiautomatic Pistol

The Scorpius from Off Grid Suppressors (Off Grid) is a compact and lightweight 22 caliber rimfire silencer, intended to suppress the .22LR cartridge.  It has a 1-inch diameter and is 5 inches long. The silencer is entirely constructed of DMLS (3D-printed) titanium.  The silencer may be installed on host weapons threaded 1/2”-28-tpi and weighs 2.2 ounces, as tested. The Scorpius can be obtained from Off Grid Suppressors and Silencer Central.

PEW Science is an independent private testing laboratory and also hosts the world’s only independent public suppressed small arms research cooperative. Testing, data analysis, and reporting for public research is generated with funding provided by PEW Science members. Any test data that is generated with any portion of private funding contains this disclosure. The testing and analysis production for this Sound Signature Review was funded in part by PEW Science Project PEW-OG-104-001-24. Therefore, data pertaining to the Scorpius in this Sound Signature Review is published with the express written permission of Rough Rider Technology.

This Sound Signature Review contains single-test results using the Off Grid Suppressors Scorpius mounted to the Beretta 21A subcompact semiautomatic pistol, chambered in .22LR with a 2.4-inch barrel. CCI Standard Velocity 40gr ammunition was used in the test.

  • Section 6.188.1 contains the Off Grid Scorpius test results and analysis.

  • Section 6.188.2 contains Suppression Rating comparisons with selected .22 rimfire silencers in the subsonic cartridge regime.

  • Section 6.188.3 contains the review summary and PEW Science laboratory staff technical opinions.

Summary: When paired with the Beretta 21A subcompact semiautomatic pistol and fired with CCI SV .22 LR ammunition, the Off Grid Scorpius achieved a composite Suppression Rating™ of 82.0 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.

6.188.1 Off Grid Suppressors Scorpius Sound Signature Test Results

A summary of the principal Silencer Sound Standard performance metrics of the Off Grid Suppressors Scorpius is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. The data acquired 0.15 m (6 in) right of the shooter’s ear is only available to membership supporters of PEW Science and the Silencer Sound Standard. You can support public PEW Science testing, research, and development with a membership, here. State-of-the-art public firearm sound signature testing and research conducted by PEW Science is supported by readers like you.

 

Table 1. Off Grid Suppressors Scorpius Sound Metric Summary

 

6.188.1.1 SOUND SIGNATURES AT THE MUZZLE

Real sound pressure histories from a 6-shot test acquired with PEW-SOFT™ are shown below. Six cartridges were loaded into the magazine and the weapon was fired until the magazine was empty; the Beretta 21A pistol does not possess a last round bolt hold open feature, and thus the slide does not lock back on the last round fired. In this test, a weapon malfunction occurred during Shot 6 preventing the slide from returning to battery, thus the slide-closing signature is not present in the measured Shot 6 signatures.  Regardless, only five shots are considered in the analysis, to maintain consistency with the overall PEW Science public dataset.  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 are shown in Figure 1a. A zoomed-in timescale displays the region of peak sound pressure in Figure 1b, of the first two shots. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 2. Again, full and short timescales are shown, this time of Shots 1, 2, and 3.

Fig 1a. Off Grid Suppressors Scorpius Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Muzzle Sound Pressure Signature

Fig 1b. Off Grid Suppressors Scorpius Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Muzzle Sound Pressure Signature, Short Time Window

Figure 2a. Off Grid Suppressors Scorpius Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Muzzle Sound Impulse Signature

Figure 2b. Off Grid Suppressors Scorpius Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Muzzle Sound Impulse Signature

The Off Grid family of silencers consists of monolithic 3D printed direct thread models.  Other Off Grid silencers evaluated by PEW Science include the Trident Ti on .308 bolt-action (6.165) and the Operator Ti on 5.56 MK18 (6.166).  Like the Trident Ti and Operator Ti centerfire rifle silencers, the Off Grid Scorpius rimfire silencer incorporates internal geometry indicative of modern hybrid technology.  Hybrid silencers combine elements of conventional baffle designs with added elements, and sometimes also high flow rate geometries such as those implemented in HUXWRX Flow-Through technologies, and others.  The performance of several different hybrid silencer technologies is examined in the following PEW Science Member Research Supplements:

PEW Science Research Note 1:  The Off Grid Scorpius is very similar in design, size, and weight to the Mercy Firearms Pluto (6.146).  However, unlike the Pluto, the Scorpius possesses an inner lattice structure around the main baffle core. PEW Science laboratory testing indicates the lattice specifically increases suppression efficiency; it is postulated that the increased turbulence that increases the efficiency of heat transfer works in tandem with the increased surface area to do the same.  Some unique performance features of the silencer include:

  1. The first-round-pop (FRP) quenching mechanism, highlighted in Figure 2b.  Note that after peak FRP is reached (pressure space, Fig. 1b), throttle occurs. Blast momentum accumulation in the positive phase does not resume until later in time, after initial jetting.

  2. Consistent, low blast pressure propagation performance (Fig. 1a and Fig. 2a).

  3. No apparent loss of suppression efficiency later in the shot string (Fig. 2a).

The FRP quenching behavior from the Scorpius results in masking of relative FRP severity to bystanders on this short-barrel pistol host.  This is a noteworthy performance trait, as FRP suppression with short barrels is a challenging performance requirement for all silencers in all combustion regimes. It is much more difficult for a rimfire silencer to suppress relative FRP severity on a short-barrel semiautomatic subcompact handgun than it is to do the same on a long-barrel bolt-action rifle.  The input muzzle blast loads from a 16-in bolt action rifle, with CCI Standard Velocity .22LR cartridges (the test ammunition), are significantly less severe than from the 2.4-in barrel semiautomatic pistol.

PEW Science Research Note 2: The Off Grid Scorpius’s FRP masking capabilities on this host weapon slightly exceed those of the relatively high performing Otter Creek Labs Titanium (6.150).  However, on average, the pure suppression performance of the Titanium is nominally higher than that of the Scorpius, as reflected in their muzzle (bystander) Suppression Ratings.  The FRP masking capabilities of these silencers on short barrel weapons are notable.  Another example of notable FRP masking occurs with the CAT SR (6.141); an advanced hybrid.  Both the Rugged Oculus (6.2) and Resilient Suppressors  Jessie’s Girl (1.36) are unable to achieve this type of FRP masking on this host weapon.  It is important to note that the resulting signature mechanism occurring with both the Scorpius and Titanium is not unique to rimfire suppression; this type of FRP signature severity masking also occurs in other combustion regimes on completely different weapon systems and with completely different silencers in the free field, such as with the Thunder Beast ULTRA 9 (6.24) and the long configuration of the Rugged Surge (6.22) fired on .308 bolt-action platforms.

PEW Science Research Note 3:  The consistency of the Off Grid Scorpius signatures, post-FRP, is notable.  Within the scope of this test program and the pressure amplitude and time regimes of .22LR combustion, PEW Science postulates that the overall behavior of the Scorpius on this host type should provide users with consistent free field suppression performance on semiautomatic rimfire pistols.

PEW Science Research Note 4: The Off Grid Scorpius is not an extreme low-backpressure system. However, the lattice structure that augments its conventional baffle design provides significant suppression efficiency in the size envelope.  As backpressure becomes a greater factor for a suppressed rimfire pistol system, shooter hazard may increase accordingly.  This type of performance differential is measurable and there is precedent for it in the research pedigree in the examination of the test program results for the CAT SR; its implementation of SURGE BYPASS technology to reduce system backpressure is significantly advanced. The requisite early-time flow rate increases to achieve such performance, combined with late-time gas momentum throttling to maintain high pressure field suppression, are seldom present in silencer designs, in general, let alone rimfire silencer designs.  It is notable that the Scorpius can achieve the Suppression Rating metrics it does on this host, especially for it size.

PEW Science Research Note 5: The rimfire silencer short-barrel pistol suppression performance Rankings are now expanding; the Off Grid Scorpius joins the Otter Creek Labs Titanium, the CAT SR, the Resilient Suppressor’s Jessie’s Girl and the Rugged Oculus (in two configurations) in the current published dataset.  Again, users should note that performance of rimfire silencers on long and short barrels may be significantly different, even with subsonic ammunition, depending on silencer design. These performance differentials are the subject of ongoing PEW Science research.

The signatures measured at the operator’s head are presented and analyzed in the full Member Version of this report.

Further comparison of the Off Grid Scorpius rimfire pistol suppression performance is provided below.

6.188.2 Suppression Rating Comparison - Semiautomatic Subsonic .22 LR

The Off Grid Scorpius was developed to maximize pure sound signature reduction (PEW Science Suppression Rating) regardless of rimfire host, in a very lightweight design envelope.  Figure 6 shows a performance comparison of rimfire silencer configurations tested on a subcompact semiautomatic pistol shown in public PEW Science testing, to date. Suppression Ratings are shown for both the shooter and bystanders.

Figure 6. Suppression Rating Comparisons Of Rimfire Silencers Using PEW-SOFT subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Test Data

The performance of the Off Grid Scorpius on the short-barrel subcompact semiautomatic rimfire pistol platform is high; not only for its size, but in general.  The use of annular lattice structure is postulated to produce higher performance efficiency than the similarly designed Pluto silencer on this host weapon.  The Off Grid Scorpius exhibits the 2nd highest shooter’s ear (operator) sound field suppression performance on this host weapon system in the current dataset.  Only the CAT SR exceeds its performance; the CAT SR being both longer and more advanced (see Research Note 4).

The performance gap between the Scorpius and configurations like the short configuration of the Rugged Oculus are nontrivial; the two configurations have a differential of several categories on the Suppression Rating scale.  With a high degree of FRP masking performance, light weight, small size, and significant pistol suppression performance, the Scorpius represents a significant performance benchmark for hybrid design rimfire silencers in the current state of practice.

The consistency of the Off Grid Scorpius pays significant dividends in total pressure field suppression performance and enables it to nominally exceed the shooter’s ear suppression performance of the Otter Creek Labs Titanium and exceed the performance of the Resilient Suppressors Jessie’s Girl in totality, in a smaller and lighter design. 

The signature of a high performance rimfire silencer with subsonic ammunition fired from a semiautomatic pistol is significantly suppressed and may not sound like a “gunshot” to the operator or to bystanders.  When such systems enter the 80-zone on the Suppression Rating scale on a reciprocating weapon, the signatures have a large proportion of audibly discernable mechanical noise.  It is important for operators and bystanders to remain cognizant of the potential hazards of firearm use and the potential lethality of such weapon systems; the operation of such systems, if not in accordance with weapon and silencer manufacturer instructions, may still result in serious injury or death.  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.

6.188.3 Review Summary: Off Grid Suppressors Scorpius on a Beretta 21A Subcompact Semiautomatic Pistol

When paired with the Beretta 21A subcompact semiautomatic pistol and fired with CCI SV .22 LR ammunition, the Off Grid Scorpius achieved a composite Suppression Rating™ of 82.0 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 Off Grid Suppressors Scorpius is a compact and lightweight rimfire silencer that exhibits extremely competitive suppression performance on short-barrel rimfire systems such as pistols. The silencer is 3D-printed from titanium and may be cleaned with a variety of chemical solutions.  At only 5 inches long, and weighing approximately 2.2 ounces, the Off Grid Scorpius demonstrates extremely competitive overall performance not only for its size, but also relative to larger rimfire silencers.

The Off Grid Scorpius is very similar in design, size, and weight to the Mercy Firearms Pluto.  However, unlike the Pluto, the Scorpius possesses an inner lattice structure around the main baffle core. PEW Science laboratory testing indicates the lattice specifically increases suppression efficiency; it is postulated that the increased turbulence that increases the efficiency of heat transfer works in tandem with the increased surface area to do the same.  Some unique performance features of the silencer include FRP quenching behavior that results in masking of relative FRP severity to bystanders on this short-barrel pistol host.  This is a noteworthy performance trait, as FRP suppression with short barrels is a challenging performance requirement for all silencers in all combustion regimes. It is much more difficult for a rimfire silencer to suppress relative FRP severity on a short-barrel semiautomatic subcompact handgun than it is to do the same on a long-barrel bolt-action rifle.

The consistency of the Off Grid Scorpius pays significant dividends in total pressure field suppression performance and enables it to nominally exceed the shooter’s ear suppression performance of the Otter Creek Labs Titanium and exceed the performance of the Resilient Suppressors Jessie’s Girl in totality, in a smaller and lighter design. The performance gap between the Scorpius and configurations like the short configuration of the Rugged Oculus are nontrivial; the two configurations have a differential of several categories on the Suppression Rating scale.  With a high degree of FRP masking performance, light weight, small size, and significant pistol suppression performance, the Scorpius represents a significant performance benchmark for hybrid design rimfire silencers in the current state of practice.

The Off Grid Scorpius silencer may not be disassembled, therefore, it must be cleaned by soaking it in a chemical solution, or in an ultrasonic cleaner.  The user is encouraged to contact the manufacturer for maintenance recommendations, as rimfire platforms may produce a significant amount of lead buildup that can degrade suppression performance over time.

PEW Science has not evaluated the durability of the Off Grid Scorpius, nor its performance on cartridges other than subsonic .22 LR.  It is important for the user to contact the manufacturer to determine the suitability of firing schedules and use cases.

In this review, the Off Grid Scorpius performance metrics depend upon suppressing a subsonic rimfire cartridge on a subcompact semiautomatic rimfire pistol, which is a difficult task. While the sound signature of such systems can be suppressed to levels that may not sound like a “gunshot” to the operator or to bystanders, PEW Science encourages the reader to remain vigilant with regard to all subsonic rimfire cartridge suppression claims.  It is important for operators and bystanders to remain cognizant of the potential hazards of firearm use and the potential lethality of such weapon systems; the operation of such systems, if not in accordance with weapon and silencer manufacturer instructions, may still result in serious injury or death. 

The hazard potential of subsonic rimfire pistol use is not insignificant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.