SSS.6.237 - Blackbird F556 and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle (Free Version)
/Blackbird F556 on the MK18 5.56x45mm AR15 with 10.3-in Barrel
The F556 is designed by Blackbird Suppressors. It is a .243 caliber (6mm) centerfire rifle silencer, optimized to suppress the 5.56x45mm NATO cartridge and is also compatible with .243 cartridges such as 6mm ARC. It has a 1.63-in diameter and is 5.4 inches long with no mount installed. The rear of the silencer is threaded 1.375-24tpi to accommodate “HUB” compatible mounting systems; the included direct-thread mount increased the total tested system length to 5.78 inches. The silencer is offered in both 3D-printed titanium and Haynes 282 (nickel-chromium-cobalt alloy). The titanium model was evaluated in this test program; the core of the silencer weighs 8.1 ounces and the direct-thread mount weighs 2.5 ounces, for a total system weight of 10.6 ounces, as tested. The F556 can be obtained from Silencer Shop.
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 8.1.34 for further details. The PEW-SOFT HD Blast Hazard Prediction Tool and Hazard Mapper is presented in Report 8.1.1.
Performance Note:
PEW Science evaluated the HUB compatible titanium silencer test specimen in this program with the included direct-thread mount. Separately, internal manufacturer testing conducted by Blackbird Suppressors on the QD Haynes model with the Blackbird muzzle device yielded similar blast testing results. PEW Science examined Blackbird’s test data and made a determination, with a reasonable degree of confidence, that the test results documented in this report are likely representative of both silencer versions on this weapon system. Some observed differences do exist regarding signature consistency, such as the tested titanium model being somewhat less consistent which is hypothesized by PEW Science to be driven by heat soak phenomena due to lower thermal mass. There are also some differences in early-time blast impulse accumulation behavior between the two different mounting systems, which stands to reason given the technology in the silencer. Overall, it is likely that the performance of the direct-thread and muzzle device-mounted versions is reasonably congruent on this weapon system.
Blackbird F556 10.3-in MK18 AR-15 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
PEW Science is an independent private testing laboratory and also hosts the world’s only independent public suppressed small arms research cooperative. Testing, data analysis, and reporting is generated with funding provided by PEW Science members. Any test data that is generated with any portion of private funding contains this disclosure. The testing and analysis production for this Sound Signature Review was funded in part by PEW Science Project PEW-BB-142-001-26. Therefore, data pertaining to the F556 in this Sound Signature Review is published with the express written permission of Blackbird Suppressors.
The testing and analysis presented in this Sound Signature Review is of the Blackbird F556 mounted with the included direct-thread mount on the MK18 Automatic AR15 rifle, chambered in 5.56x45mm NATO with a 10.3-inch barrel. Federal XM193 55gr ammunition was used in the test. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.
Report Table of Contents:
Section 6.237.1 contains a Blackbird F556 performance summary comparison with other silencers that form the extreme ends of the Personnel Risk spectrum on a suppressed 5.56 AR-15 SBR.
Section 6.237.2 contains Blackbird F556 test results and analysis on the standard untuned MK18.
Section 6.237.3 contains overall Suppression Rating comparisons of the Blackbird F556 with dedicated 223 and 30 caliber silencers on the current market, including the Otter Creek Labs Infinity 556K, Rampart Range Carson 30, Dead Air Lazarus 6, Otter Creek Labs Universe-36, JK Armament PRO-KOR 556K, Stealth Additive Works Tisha, CAT CACM 556, CAT KK, FOR Systems Monarch Recce, Engaged Industries Operator 5.56, Q Southpaw, Centurion Arms Maximus-L, Otter Creek Labs Infinity, PTR VENT Spiritus 556i, LMT AT ION LT, HUXWRX FLOW 556 Ti, Off Grid Operator Ti, Surefire SOCOM556-MINI2, KAC QDC/CRS-PRT, KAC QDC/MCQ-PRT, Surefire SOCOM556-RC3, Otter Creek Labs Polonium-30, AAC M4-2000 Mod 08, PTR VENT 3, SilencerCo Velos LBP, BOSS Guillotine, CAT WB, PWS BDE 556, CAT ODB, Aero Precision Lahar-30L, Lahar-30, HUXWRX FLOW 762 Ti, Maxim Defense DSX, Thunder Beast Dominus, KAC 5.56 QDC, CGS SCI-SIX, Dead Air Nomad-30, YHM Turbo T2, Dead Air Sandman-S, HUXWRX FLOW 556k, Energetic Armament ARX, KAC QDSS-NT4, Rugged Razor556, Otter Creek Labs Polonium and Polonium-K, Surefire SOCOM556-RC2, HUXWRX HX-QD 556 and HX-QD 556k, Q Trash Panda, CGS Helios QD, SilencerCo Saker 556, Rugged Razor762, and others.
Section 6.237.4 contains an article summary and PEW Science laboratory staff opinions.
Summary: When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the Blackbird F556 with the direct-thread mount achieved a composite Suppression Rating™ of 43.7 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.
6.237.1 Blackbird F556 Performance Summary and Extreme Ends of Personnel Risk on a Suppressed 5.56 AR-15 SBR
Not all centerfire rifle silencers produce the same suppression performance. Not all silencer technology is created equal.
The suppression performance of a silencer on a given small arm weapon system dictates the following two parameters:
Personnel protection of the operator and bystanders from blast overpressure hazard, both in the free field and near surfaces and in confined spaces. Blast overpressure at amplitudes generated by small arms can harm a human’s inner ears and brain.
Signature detection by adversaries. Muzzle blast is the primary audible source that may be suppressed to mask position.
Historical public research by PEW Science in the Silencer Sound Standard has produced a dataset suitable for examination of technology performance trends, particularly in the case of short barrel reciprocating weapon systems firing the 5.56x45mm NATO intermediate rifle cartridge.
This report presents a third-party laboratory performance evaluation of the Blackbird F556 silencer on the standard untuned 10.3-in MK18. The Blackbird F556 produces performance that places it in the Top 5 MK18 Rankings as of the date of this report publication. It is therefore useful to summarize both the Top 5 performers and Bottom 5 performers, so that the aforementioned performance realities can be easily understood by the reader, contextually. The reader may sort and filter all public Rankings here.
Objectively, the top five performers are the safest for personnel and are likely to mask operator position from adversaries to the greatest degree. Also objectively, the bottom five performers produce the most dangerous environment for personnel and are likely to provide the least concealment of audible signature.
The top five performing systems on the MK18 showcased in public evaluations are:
Blackbird F556 (this report)
The bottom five performing systems on the MK18 showcased in public evaluations are:
The performance disparity between the top 5 silencers and bottom five silencers is the result of technological advancement and cartridge specialization driven by public research. All 5 top performers are hybrid designs. Two (the Surefire silencers), and arguably one (the KAC silencer) have hybrid design elements that pre-date the rest of the group. Surefire hybrid technology was derived from early OPS Inc. technology (see here).
The modern hybrid designs provide the greatest performance potentials while balancing operator and bystander protection and weapon system reliability and longevity. Specifically, these types of silencers use early venting and different pressure stages to relieve stagnation and increase suppression efficiency in a given design envelope, while also significantly reducing back pressure. Hybrid designs are not Flow Through silencers, and misclassification is commonplace in the silencer industry; no Flow Through silencers exist other than those manufactured by HUXWRX (formerly OSS). For more details, performance evaluations, and in-depth signature comparisons of hybrid and conventional designs, the reader may examine analysis that is previously published in:
Member Research Supplement 6.103 (supersonic 5.56 NATO)
Member Research Supplement 6.115 (supersonic 7.62 NATO)
Member Research Supplement 6.124 (subsonic 300 BLK)
Member Research Supplement 6.169 (supersonic 5.56 NATO), and recently
Member Research Supplement 6.184 (subsonic 9mm).
To be clear, it is not the addition of a single design element that produces high performance from a small arm weapon system silencer. It is the combination and purposefully engineered integration of multiple design elements that give way to high holistic system performance.
The raw performance of the Blackbird F556 is illustrated in Figure 1 below, along with the remainder of the aforementioned top 5 and the bottom 5 performing silencers on the MK18. The 3D-printed internal structure of the Blackbird F556 not only possesses expedient blast chamber venting, but annular spiral geometry and interstitial baffle venting. Its flow rate is relatively high and its blast momentum propagation is relatively controlled (significantly controlled in very early time, when compared to the silencers in the MK18 dataset at large).
The host weapon system in Figure 1 is kept constant, and metrics shown are in terms of PEW Science Suppression Rating, which is a human risk metric calculated from raw free field blast overpressure test data. The calculated risk metrics for the unsuppressed case are also presented.
Figure 1. Suppression Rating Comparisons of the Top 5 Safest and Most Dangerous rifle silencers Using PEW-SOFT 5.56x45mm Supersonic MK18 Test Data and PEW Science Analysis
From the above data, two primary conclusions are apparent:
Silencer over-bore, in general, may reduce suppression performance. Both Surefire silencers and the Rugged silencer are 7.62 weapon system silencers that found historical popular and industry-recommended use on 5.56 weapon systems. The Energetic Armament silencer was purposely over-bored in an effort to reduce baffle erosion under heavy firing schedules. The KAC silencer is not significantly over-bored, but is relatively primitive in its design and its technology is not appropriate to produce high performance in the given system length envelope. Note that there are exceptions to over-bore performance reductions. That discussion is outside the scope of this report.
Rifle silencer suppression technology continues to advance at a rapid pace. The Stealth Additive Works, CAT SURGE BYPASS, and PTR PIP technologies are all extremely advanced. The Infinity technology in the Carson 556 gives way to another advanced hybrid design. The Staged Pressure Vectoring technology in the Blackbird F556 shares some similarities with other hybrid designs in that it possesses early-time venting and lengthened annular flow paths. In general, these systems are optimized and produced with advanced manufacturing.
Additive manufacturing is required in order to implement the engineering solutions present in many of the most advanced silencers. However, it is not only purposeful design and advanced manufacturing that can contribute to high performance for the end user. Some designs perform better than others, even in the same size classes; there are clear behavioral differences that are showcased with real measured test data and engineering analysis. The performance differentials may be nontrivial, even between new technologies released today. The above metrics are calculated from test data generated on a standard untuned host; weapon system tuning may raise performance potentials, as has been demonstrated in previous public research.
Detailed Blackbird F556 test data and analysis follows.
6.237.2 Blackbird F556 Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Blackbird F556 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. Blackbird F556 Sound Metric Summary
6.237.2.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories from a 6-shot test acquired with PEW-SOFT™ are shown below. Six cartridges were loaded into the magazine, the fire control group positioned to single-shot, and the weapon was fired until the magazine was empty and the bolt locked back on the follower of the empty magazine. Only five shots are considered in the analysis. The signatures of Shot 6 are displayed in the data presentation but are not included in the analysis to maintain consistency with the overall PEW Science public dataset and bolt-closing signatures. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science laboratory sound signature testing is 1.0 MS/s (1 MHz). The peaks, shape, and time phasing (when the peaks occur in relation to absolute time and to each other) of these raw waveforms are the most accurate of any firearm silencer testing publicly available. PEW-SOFT data is acquired by PEW Science independent laboratory testing; the recognized industry leader in silencer sound research. For more information, please consult the Silencer Sound Standard.
The primary sound signature pressure histories for all 6 shots with the Blackbird F556 are shown in Figure 2a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 2b, in early time. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 3a. In Figure 3b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shots 2, 3, and 5.
Fig 2a. Blackbird F556 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature
Fig 2b. Blackbird F556 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature
Figure 3a. Blackbird F556 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
Figure 3b. Blackbird F556 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
The Blackbird F556 is an advanced hybrid design with significantly notable performance for its size. Somewhat atypical is the geometry in its first expansion (blast) chamber. The chamber possesses four longitudinal vent channels and also angular longitudinal surface protrusions around its entire internal diameter. Annular flow is fed by the aforementioned vent channels and interstitial baffle vents; the annulus has spiral array elements which are now considered common in the current design state of practice. The totality of these features is named Staged Pressure Vectoring technology by Blackbird Suppressors.
Like several advanced hybrids with similar above features, the F556 controls blast momentum propagation relatively well even on the short barrel MK18 weapon system. The performance of the F556 is particularly balanced throughout the personnel risk field, as illustrated in the Hazard Map at the beginning of this report and in Silencer Hazard Map Brief 8.1.34.
PEW Science Research Note 1: Despite the gross similarity in average hazard reduction performance of the F556 when compared to some competing designs, there are specific observations in the raw blast test data that highlight how the Blackbird technology behaves:
Low amplitude free field blast overpressure with moderate blowdown duration and relatively late time bolt carrier group (BCG) return to battery (Fig. 2a).
Extremely consistent precursor events and first coupled jets followed by significantly throttled jet delay (Fig. 2b).
Major first-round-pop (FRP) jetting followed by significant FRP rarefaction signifying high FRP momentum (Fig. 2b).
Consistent early stage momentum in subsequent shots, congruent momentum delay with (2), with later stage increases in momentum accumulation rate (Fig. 3b).
Peak momentum is shown to increase as the shot string continues (Fig. 3b).
Observation (1) demonstrates balanced suppression and flow performance, though the significant jet delay observed in (2) and (4) does indicate some flow rate drop. The momentum rate increases in (4) and (5) potentially indicate heat soak driven efficiency losses. While such momentum increases are sometimes systemic in a silencer design, blast testing results of the Haynes model by Blackbird Suppressors were examined by PEW Science and suggest otherwise in this case; a preliminary determination, with a reasonable degree of confidence, is that the Haynes version of the silencer is somewhat more consistent due to higher thermal mass. There are some other unknowns, including mount factors, that prevent that determination from being definitive. Regardless, the performance of the two versions of the silencer are likely reasonably congruent. Observation (3) is most certainly design driven, present in both silencer versions, and may be a consequence of the first expansion chamber and vent geometry.
PEW Science Research Note 2: In summary, the above observations indicate that the Staged Pressure Vectoring technology in the Blackbird F556 demonstrates performance attributes that are a mix of those demonstrated by some other high performance hybrid designs on the current market discussed in the previous section of this report, but in a smaller size envelope. For example:
On average, the F556 performs similarly to a PTR VENT 3 (6.135) but in a significantly shorter envelope and with somewhat less consistency. FRP of both silencers is noticeable and not masked.
The overall average F556 performance is very similar to the slightly longer CAT CACM 556 (6.203), but whereas the CACM silencer throttles blast load at a lower amplitude and blows down faster with a very high degree of FRP control, the F556 delays initial blast propagation with later higher peak amplitude and somewhat longer blowdown. The average Suppression Ratings of the two silencers are extremely similar. The initial blast propagation delay may be a function of the aforementioned first expansion chamber design. This may represent a flow rate drop.
The Blackbird F556 essentially behaves like a less consistent CACM 556 with similar FRP to a VENT 3. The FRP from the F556 is noticeable to bystanders in the free field, but it is important to note that its FRP signature is less severe than all shot signatures from lower performance silencers. At the highest echelons of 5.56 suppression performance demonstrated by silencers like the Stealth Additive Works Tisha (6.209) and the CAT ST (6.217), FRP is effectively masked and consistency can be very robust. Note that the CAT ST was tested on the 14.5-in M4 in the referenced report but 10.3-in MK18 testing demonstrates comparable consistency and robust FRP control. Also note that the Tisha tested in the referenced report was a titanium version that demonstrated likely heat soak related impulse accumulation behavior. In the case of both the Blackbird F556 and the Tisha, practical signature severity variation through the shot string is somewhat less impactful to observers than it is with lower performing silencers.
PEW Science Research Note 3: At the time of writing, the measured performance of the Blackbird F556 places it solidly in the top 5 of the overall MK18 PEW Science Rankings, slightly above the aforementioned CACM 556. As tested, the CACM is slightly (0.3-in) longer than the F556. The Blackbird silencer has relatively balanced performance; its elevated shooter’s ear (operator) Suppression Rating further differentiates it from silencers like those using Otter Creek Labs Infinity technology such as the Rampart Range Carson 556 (6.226), Otter Creek Labs Infinity (6.179), and Infinity 556k (6.233), elevating its Composite Suppression Rating. For further context regarding both performance and size balance, the reader is encouraged to use the Suppression Rating Parametric Visualization Tool (Members Only) for independent study. The overall average suppression performance of the Blackbird F556 is extremely notable given its total 5.8-in tested length (5.4-in without a mount).
PEW Science Research Note 4: It is extremely important for the reader to understand the Suppression Ratings are computed with free field test data, and are therefore universal when translating the weapon and operator to different environments without reflections. However, when the environment becomes complex with many reflecting surfaces, performance translation of different systems is not yet possible; sound field shapes and particle velocities result in varied blast wave time-of-arrivals, as well as changes of blast load angles of incidence; these variations change amplitude and phase waveform components. As a result of these inevitable environmental complexities, user impressions will vary, as both the shooter and bystander. Nonetheless, hazard reduction efficacy in the free field, as characterized by the Suppression Rating, holds. The Suppression Rating comparisons are the current state-of-the-art, and the most “apples to apples” sound suppression performance comparisons that currently exist. Further research is ongoing. The reader should note that shooting a Blackbird F556 indoors and a HUXWRX FLOW silencer indoors may result in different blast overpressure risk profiles.
PEW Science Research Note 5: As in all semiautomatic AR-15 weapon testing, a second pressure pulse originates from the ejection-port signature of the weapon and it occurs early enough in time such that its waves coalesce with that of the muzzle signature. However, in late time (at approximately 90 ms in Figure 2a) the mechanical noise of the bolt closing is observed. The pressure signature of Shot 6 does not display this event due to the bolt remaining open after the sixth and final round is fired from the magazine.
PEW Science Research Note 6: The closing time of the AR-15 bolt is directly related to the flow restriction of a silencer for a given weapon system. PEW Science has determined bolt closing time variation from the unsuppressed state to be a reliable indicator of silencer back pressure, with strong correlation with the PEW Science Back Pressure Metric, Omega and the alpha parameter. However, PEW Science has also determined that the indicator is unreliable upon upper receiver fouling. Sound signatures are not influenced by this fouling, as these kinematics occur in late time, after gas venting to atmosphere. Momentum transfer, weapon condition (upper receiver fouling), and other factors, can significantly influence bolt closing time. PEW Science urges the reader to exercise extreme caution if using the published bolt closing time to make determinations regarding silencer flow restriction (back pressure) or weapon system kinematics. This type of calculation may provide erroneous results, as the weapon condition at the time of each test is not published data. The time-scale duration showing bolt closing time is only published by PEW Science such that the signature data pedigree may be verified.
The shape, timing, and magnitudes of the early-time pressure pulses and overall shape of the impulse waveforms measured at the muzzle, from shot-to-shot, are relatively consistent. The consistency of the waveform amplitudes highlight the silencer’s overall sound performance consistency at the muzzle after the FRP, as well as the relative consistency of the tested automatic rifle firearm configuration.
As typically indicated, first-round sound signatures always differ from subsequent shots, as the atmosphere within the silencer changes. The FRP phenomenon cannot always be shown by viewing only the peak sound pressure. This is one of the reasons why The Silencer Sound Standard requires examining multiple sound signature metrics. Ammunition consistency can play a role in the determination of FRP, however, the close examination of measured pressure and impulse waveforms typically excludes ammunition from the possible factors influencing true FRP, due to the relative consistency of most high quality factory ammunition.
PEW Science Research Note 7: Note that the muzzle Suppression Rating of the Blackbird F556 is 43.4 and the at-ear Suppression Rating is 29.6; different zones on the Suppression Rating Dose Chart, but both higher than typical on this weapon system. The lower back pressure of the F556, along with its strong average muzzle suppression, contributes to a less severe ejection port blast signature, which further decreases shooter hazard on the standard MK18 weapon system. The reader is encouraged to examine the Silencer Hazard Map at the top of this report as detailed in Silencer Hazard Map Brief 8.1.34. Weapon tuning will influence hazard reduction efficacy, and is outside the scope of this study.
The signatures measured at the shooter’s ear are presented and analyzed in the full Member Version of this report. Overall performance comparisons on the standard MK18 rifle are provided below.
6.237.3 Suppression Rating Comparison (5.56x45mm from the MK18)
Figure 6 presents a comparison of the PEW Science Suppression Rating of the Blackbird F556 with that of several other silencers on the MK18 weapon system. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.
Figure 6. Suppression Rating Comparisons of the Blackbird F556 and other rifle silencers, Using PEW-SOFT 5.56x45mm Supersonic Test Data and PEW Science Analysis
Figure 6 presents an overall summary of the postulated hazards to the operator and bystanders when fielding a variety of different silencers on the standard MK18 weapon system. The Blackbird F556 from this test program is shown in red. Hazards are expressed with the Suppression Rating; a holistic parameter that captures human inner ear damage risk potential from a measured impulsive complex blast 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 and Hazard Map 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. Analytically computed metrics are color-coded in the Rankings Table, in all Silencer Hazard Maps, and keyed to the dose chart for user interpretation.
The following gross conclusions can be made from the metrics presented in Figure 6, above:
The Blackbird F556 produces free field bystander hazard reduction on par with the following silencers on the MK18 weapon system:
The free field operator (shooter) hazard reduction of the Blackbird F556 with the standard untuned MK18 weapon system is higher than it is with several other designs due to its higher flow rate (lower back pressure) and its relatively efficient muzzle suppression for its size. The MK18 operator protection with the F556 is on par with or exceeding that of the:
The top five performing systems on the MK18 showcased in public evaluations are:
Blackbird F556 (this report)
The bottom five performing systems on the MK18 showcased in public evaluations are:
PEW Science Research Note 10: Without weapon system tuning, operator hazards from a suppressed MK18, in the free field, plateau at Suppression Ratings near 30. This is due to ejection port blast loads. However, this does not mean that silencers with similar shooter’s ear Suppression Ratings will sound the same to the shooter, in the free field. On the contrary, what an operator hears through the entire time regime of a gun shot event and subsequent environmental reflections, and which acute hazards manifest, may be different. The reader is strongly encouraged to review the published Silencer Hazard Map at the top of this report and in Silencer Hazard Map Brief 8.1.34. Furthermore, to illustrate two extremes, the difference in spatial hazards from a Flow Through silencer and a high back pressure silencer are directly compared in Silencer Hazard Map Brief 8.1.5 (HUXWRX FLOW 556k vs. SilencerCo Saker 556).
As stated in Research Note 3, at the time of writing, the measured performance of the Blackbird F556 places it solidly in the top 5 of the overall MK18 PEW Science Rankings, slightly above the aforementioned CACM 556. As tested, the CACM is slightly (0.3-in) longer than the F556. The Blackbird silencer has relatively balanced performance; its elevated shooter’s ear (operator) Suppression Rating further differentiates it from silencers like those using Otter Creek Labs Infinity technology such as the Rampart Range Carson 556 (6.226), Otter Creek Labs Infinity (6.179), and Infinity 556k (6.233), elevating its Composite Suppression Rating. For further context regarding both performance and size balance, the reader is encouraged to use the Suppression Rating Parametric Visualization Tool (Members Only) for independent study. The overall average suppression performance of the Blackbird F556 is extremely notable given its total 5.8-in tested length (5.4-in without a mount).
Hybrid designs continue to demonstrate significant performance with supersonic ammunition suppression, and silencers like the F556, and others, show that performance can be achieved in compact design envelopes. The performance of these next generation systems are significantly elevated when compared to that of highly prolific previous generation hybrids such as the Surefire SOCOM556-RC2 (6.52) and other newly released military silencer hybrids such as the KAC PRT family (6.156) on this weapon system. Users now have additional high performance practical options to reduce weapon system length and maintain hazard reduction.
As detailed in this report, signature at the operator’s head is a function of both muzzle and ejection port signatures from the AR-15 weapon system. Specific weapon system parameters will dictate hazard reduction efficacy.
Small arm weapon system suppression performance is a spectrum. The PEW Science Suppression Rating and the Silencer Sound Standard help quantify this spectrum for end users and industry, objectively.
6.237.4 Review Summary: Blackbird F556 on the MK18 5.56x45mm AR15 with 10.3-in Barrel
When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the Blackbird F556 with the direct-thread mount achieved a composite Suppression Rating™ of 43.7 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 Blackbird F556 is a mid- to full-size 5.56 rifle silencer with very high suppression performance and a relatively balanced flow rate. The advanced hybrid design of the F556 is offered in both titanium and Haynes 282 alloy versions and offers requisite durability and weight options based on user needs. At only 5.4-inches in length without a mount, the HUB-compatible F556 not only offers universally high suppression performance, but exceptionally competitive performance for the length. While first round signature is somewhat more severe than with some other silencers in this high performance class, its overall performance is extremely notable.
The Blackbird F556 is an advanced hybrid design. Somewhat atypical is the geometry in its first expansion (blast) chamber. The chamber possesses four longitudinal vent channels and also angular longitudinal surface protrusions around its entire internal diameter. Annular flow is fed by the aforementioned vent channels and interstitial baffle vents; the annulus has spiral array elements which are now considered common in the current design state of practice. The totality of these features is named Staged Pressure Vectoring technology by Blackbird Suppressors.
Like several advanced hybrids with similar above features, the F556 controls blast momentum propagation relatively well even on the short barrel MK18 weapon system. The performance of the F556 is particularly balanced throughout the personnel risk field, as illustrated in the Hazard Map at the beginning of this report.
The Blackbird F556 essentially behaves like a less consistent CACM 556 with similar FRP to a VENT 3. The FRP from the F556 is noticeable to bystanders in the free field, but it is important to note that its FRP signature is less severe than all shot signatures from lower performance silencers. At the highest echelons of 5.56 suppression performance demonstrated by silencers like the Stealth Additive Works Tisha and the CAT ST, FRP is effectively masked and consistency can be very robust. The titanium version of the F556 was tested; it is likely that a Haynes F556 would behave more consistently later in the shot string but FRP behavior remains unchanged.
At the time of writing, the measured performance of the Blackbird F556 places it solidly in the top 5 of the overall MK18 PEW Science Rankings, slightly above the aforementioned CACM 556. As tested, the CACM is slightly (0.3-in) longer than the F556. The Blackbird silencer has relatively balanced performance; its elevated shooter’s ear (operator) Suppression Rating further differentiates it from silencers like those using Otter Creek Labs Infinity technology such as the Rampart Range Carson 556, Otter Creek Labs Infinity, and Infinity 556k, elevating its Composite Suppression Rating. For further context regarding both performance and size balance, the reader is encouraged to use the Suppression Rating Parametric Visualization Tool (Members Only) for independent study. The overall average suppression performance of the Blackbird F556 is extremely notable given its total 5.8-in tested length.
The Blackbird F556 is only 5.4 inches long without a mount. The tested direct-thread mount increased the effective system length to 5.8 inches. The direct-thread mount and silencer interface include a tapered locking surface; the silencer is backward compatible with standard “HUB” mounting accessories. Performance with other mount types may differ in both signature suppression and back pressure; the potential performance differentials are currently unknown. Based upon the internal silencer geometry, it is hypothesized that basic flash hiders may not appreciably influence performance compared to that seen in this test program with the direct-thread mount.
Again, the titanium version of the silencer was tested. The silencer is also available in Haynes nickel-chromium-cobalt alloy and that version of the silencer is expected to offer requisite durability and longevity for aggressive firing schedules. PEW Science has not evaluated the durability of this silencer. As always, the user should remain cognizant of their personal firing schedules. The user should contact Blackbird Suppressors to ensure compatibility for their use case.
In this review, the Blackbird F556 performance metrics depend upon suppressing a supersonic centerfire rifle cartridge on a short barrel gas-operated rifle, which is an incredibly difficult task. PEW Science encourages the reader to remain vigilant with regard to all supersonic centerfire rifle suppression claims. The gas volume and combustion products created by the firing of the supersonic 5.56x45mm cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact. Silencer performance on automatic (reciprocating) rifles depends on many factors. Weapon configuration may significantly influence total suppressed small arm system performance.
The hearing damage potential of supersonic centerfire rifle use is significant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
