SSS.6.23 - Dead Air Sandman-L and the Savage Model 10 PC .308
/Dead Air Sandman-L on a Savage Model 10 .308 with 20-in Barrel
The Sandman-L is designed by Dead Air. It is a 30 caliber centerfire rifle silencer, intended to suppress most cartridges with projectiles appropriately sized to travel through the bore, up to and including 300 Winchester Magnum. It has a 1.5-inch diameter and is 8.9 inches in length with the included flat end-cap. Multiple end-cap options are available for use with the Sandman-L. The user may also choose from various Dead Air Keymount muzzle devices on which to mount the silencer to the host weapon with its welded proprietary mount. The outer tube and mount are stainless steel and the cast Stellite baffles of the inner core are fully-welded. The silencer weighs 25.4 ounces with the Keymount flash hider. The Sandman-L can be obtained from Silencer Shop.
This review contains single-test results using the Sandman-L mounted with the Keymount Flash Hider and flat end-cap on the Savage Model 10 Precision Carbine rifle, chambered in .308WIN with an 20-inch barrel. Federal XM80C 149gr ammunition was used in the test. This review concludes the PEW Science evaluation of the Dead Air Sandman series on the 20-inch barrel bolt action host weapon platform with supersonic 7.62x51mm ammunition. Future Research Supplements and other comparative articles will provide further analysis of the Sandman data presented, to date. See Sound Signature Reviews 6.11, 6.15, and 6.19 for data on the Sandman-S, Sandman-K, and Sandman-Ti, respectively.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80C, the Dead Air Sandman-L with the Keymount flash hider achieved a Suppression Rating™ of 39.2 in PEW Science testing.
6.23.1 Dead Air Sandman-L Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Sandman-L 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. Dead air Sandman-L Sound Metric Summary
6.23.1.1 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 2.6 millisecond long portion of the first round sound pressure signature of the Dead Air Sandman-L as measured 1.0 m left of the muzzle. There are three significant waveform features labeled:
An initial pressure pulse out of the silencer, after the bullet exits the end-cap, causes a 141.4 dB peak.
The measured sound pressure increases, gradually, to a maximum of 145.7 dB
As gas continues to exit the silencer from the primary combustion event, secondary jetting results in a peak of 149.7 dB.
This is the typical sequence observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer that exhibits significant flow restriction (back pressure); however, internal silencer design can significantly influence the measured timing and pressure amplitudes. Preliminary back pressure comparisons are shown in Section 6.23.2 of this review.
Fig 1. Dead Air Sandman-Ti First Round Bolt Action Rifle Muzzle Sound Pressure Signature, 09-MAY-2020
For reference, the reader is also encouraged to review the performance data of the Sandman-Ti in Sound Signature Review 6.19. The Sandman-L and the Sandman-Ti are very similar silencers, internally, but the Sandman-L possesses less internal volume due to the mandated use of a Keymount muzzle device, whereas the Sandman-Ti is a direct-thread silencer.
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 bullet end-cap exit event between all 5 shots during the test, prior to the influences of internal silencer gas environment. This event is plainly visible and decoupled from the majority of the primary combustion event due to the sample rate used with 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 0.25 milliseconds (250 microseconds) and the total timescale in Figure 2b is only 0.10 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. Dead Air Sandman-L Bolt Action Rifle Muzzle Sound Pressure Early-Time Peaks, 09-MAY-2020
Fig 2b. Dead Air Sandman-L Bolt Action Rifle Muzzle Sound Pressure Shot 1 Peak, 09-MAY-2020
The primary sound signature pressure histories for all 5 shots with the Sandman-L are shown in Figure 3a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 3b, in the regions of peak sound pressure. Note the same peak events are labeled for Shot 1 that were previously labeled in Figure 1. 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. Dead Air Sandman-L Bolt Action Rifle Muzzle Sound Pressure Signature, 09-MAY-2020
Fig 3b. Dead Air Sandman-L Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window, 09-MAY-2020
Figure 4a. Dead Air Sandman-L Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
Figure 4b. Dead Air Sandman-L Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window, 09-MAY-2020
Similar to measured behavior of the Sandman-Ti, The measured first-round-pop (FRP) is evident in both the pressure and impulse regimes using the Sandman-L. When comparing the overall early-time pressure histories of Shot 1 to Shot 2 (Fig 3b), the gas jetting in Shot 1 has a higher magnitude and faster rise-time than the jetting in Shot 2. This is best illustrated in the impulse regime in Figure 4. Note that after the initial impulse step peak occurs at approximately 29.8 ms, the slope of the impulse rise of Shot 1 is steeper than that of the subsequent shots.
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 extremely consistent, highlighting the silencer’s overall sound performance consistency at the muzzle after the FRP, as well as the relative consistency of the tested bolt action rifle firearm configuration.
PEW Science note: One notable observation from the measured data is the relatively long rise-time to peak impulse exhibited by the Sandman-L in this test, which is extremely similar to that of the Sandman-Ti. This is one objective measurement that indicates the Sandman-L exhibits higher gas flow restriction and therefore higher back pressure characteristics than the SilencerCo Omega 300 (Sound Signature Review 6.10) but is on-par with the back pressure of the Q Thunder Chicken (Sound Signature Review 6.20) and Sandman-Ti (Sound Signature Review 6.19). More detailed and direct comparisons are provided in Section 6.23.2 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.
6.23.1.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 5-shot test of the Dead Air Sandman-L suppressor 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 5. 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 and Shot 2. The real sound impulse (momentum transfer potential) histories at the ear from the same 5-shot test are shown in Figure 6. Again, full and short timescales are shown.
Figure 5a. Dead Air Sandman-L Bolt Action Rifle Ear Sound Pressure Signature, 09-MAY-2020
Figure 5b. Dead Air Sandman-L Bolt Action Rifle Ear Sound Pressure Signature, Short Time Window, 09-MAY-2020
Figure 6a. Dead Air Sandman-L Bolt Action Rifle Ear Sound Impulse Signature, 09-MAY-2020
Figure 6b. Dead Air Sandman-L Bolt Action Rifle Ear Sound Impulse Signature, Short Time Window, 09-MAY-2020
Again, like the Sandman-Ti, the Sandman-L has FRP evident when examining the waveforms measured at the shooter’s ear (Figure 5b). Note that, again, the fast rise-time to peak impulse is evident in Shot 1 (Figure 6). Also note the very similar pressure and impulse magnitudes prior to the gas completely exiting the weapon system (between 27 and 30 ms). The supersonic .308WIN platform creates significant sound signature even before the gas completely exits the weapon system, as was shown in the measured muzzle sound pressure and impulse signatures in the previous section.
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.
Note the comparable but slightly higher pressure and/or impulse measured at the weapon muzzle and at the shooter’s ear in this test of the Sandman-L than in the test of the Sandman-Ti. The Sandman-L is a slightly louder silencer than the Sandman-Ti.
6.23.2 Relative Back Pressure and Suppression Rating Comparison (.30 Rifle Silencers)
PEW Science Research Note: As of February 2021, back pressure characterization has undergone refinement and Rev.2 of the Back Pressure Metric has been developed. Research is ongoing. Please see back pressure research updates starting with Sound Signature Review 6.36.
The Sandman-L suppressor is intended to be durable and to address back pressure, even given its full size. PEW Science is currently conducting silencer back pressure research. Figure 7 shows preliminary relative 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:
The time to reach peak gas momentum transfer potential, as measured 1.0 m left of the weapon muzzle, is the objective quantity used to generate the back pressure data summary.
The waveform characteristics of unsuppressed shots with the same ammunition used in the respective tests are used in the calculations and the unsuppressed relative back pressure and Suppression Rating quantities are shown.
The first shot from each silencer test is omitted from the back pressure computations due to internal gas environment characteristics within the silencer (FRP) that influence peak impulse amplitude, wave-shape, and timing. All unsuppressed shots are included.
Back Pressure Data is normalized to the silencer with the highest back pressure and Suppression Rating shown, which is the Rugged Surge in its Long Configuration (Sound Signature Review 6.22).
Figure 7. Back Pressure And Suppression Rating Comparisons Of .308 Rifle Silencers Using PEW-SOFT Data
From the above data, it can be concluded that the Sandman-L suppressor may produce significant back pressure that is slightly lower than that of the Sandman-Ti. The reason for this slightly reduced back pressure has not been determined, and it may not be noticeable in practical use. It is important to note that the back pressure potential of silencers, in general, may not be significant in practical use with semi-automatic and automatic hosts, depending on the respective metric magnitudes; this is the subject of future PEW Science research. For example, it is postulated that there is a threshold back pressure metric below which adequate semi-automatic weapon function on 5.56x45mm host weapons may be achieved. Whether that threshold is 0.36 in Figure 7 (Sandman-S) or 0.54 (Radiant), for example, will depend on the particular host weapon configuration. Recent PEW Science research at the time of this review publication indicates that a back pressure metric threshold is probable for gas operated 5.56x45mm small arms. Further research is ongoing.
PEW Science note: The relative back pressure percentages described in this section are only valid when examining the data normalized to the Rugged Surge in its long configuration in Figure 7. PEW Science back pressure research is ongoing. Membership contributions to PEW Science help fund such research.
The Dead Air Sandman-L is quieter than mid-size 30 caliber rifle silencers, like the Trash Panda and Sandman-S, but is predicted to exhibit significantly higher back pressure. The Sandman-L is slightly quieter than the SilencerCo Omega 300, but does not reach the level of sound signature suppression exhibited by other full-size silencers such as the Sandman-Ti, the Rugged Surge, the Q Thunder Chicken, or the CGS Helios QD with its solid end-cap. It is postulated that the Sandman-L may sound similar to the Sandman-Ti, to some users. In-depth comparative analysis of these two silencers is the subject of future PEW Science research.
6.23.3 Review Summary: Dead Air Sandman-L on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80C, the Dead Air Sandman-L with the Keymount flash hider achieved a Suppression Rating™ of 39.2 in PEW Science testing.
PEW Science Subjective Opinion:
The Dead Air Sandman-L is a full-size 30 caliber machine gun rated rifle silencer that possesses relatively high sound signature suppression performance with back pressure slightly lower than that of the Sandman-Ti. The silencer is advertised to have extreme durability and is one of the heavier silencers on the market for its size, at a total system weight of 25.4 ounces.
This review concludes the PEW Science evaluation of the Dead Air Sandman series on the 20-inch barrel bolt action host weapon platform with supersonic 7.62x51mm ammunition. Future Research Supplements and other comparative articles will provide further analysis of the data presented, to date.
Like the other Sandman series 30 caliber suppressors from Dead Air, the Sandman-L uses an iteration of a feature-reduced and modified stepped-cone baffle, similar to the feature-reduced curved-cone baffle used in the Omega 300 from SilencerCo and other companies, with the primary difference being an enlarged center orifice to facilitate higher axial gas flow rate. However, because of the length of the Sandman-L (and its sister silencer, the Sandman-Ti), the silencer inhibits more gas flow than the Sandman-S, for example, and therefore produces higher back pressure. The back pressure generation of the Sandman-L is higher than that of the SilencerCo Omega 300 but marginally lower than that of the Sandman-Ti and Q Thunder Chicken. The Sandman-L slightly outperforms the shorter Omega 300 in sound suppression but does not reach the level of sound suppression measured with the Rugged Surge, Thunder Chicken, or Sandman-Ti. No centerfire rifle silencer shown in public reviews by PEW Science, to date, has surpassed the at-ear Suppression Rating of the CGS Helios QD with its solid endcap. As previously stated in the review of the Sandman-Ti, PEW Science data indicates that silencers with technology similar to that used in the Sandman-L may have now reached their sound performance thresholds and further optimization may not yield significant sound suppression performance dividends in the present design envelope. This is the subject of ongoing research.
As stated in other reviews of the Sandman series of silencers, the ratcheting proprietary mount welded to the rear of the Sandman-L that interfaces with Dead Air Keymount muzzle devices is relatively simple to operate. The mount can facilitate the installation of the silencer underneath a handguard or on barrels that have exterior obstructions which may prevent the fastening of traditional locking collars. This capability is achieved by rotating the entire silencer body during installation, rather than actuating a localized mount ring or lever. However, it is important to note that radiant heat during use of a silencer placed under the handguard of a semiautomatic rifle can be significant. PEW Science urges users to consider radiant heat when deciding on specific silencer mounting configurations.
The use of the Keymount muzzle devices with the Sandman-L results in less internal silencer volume and it is postulated that is one of the reasons why the Sandman-L exhibits slightly lower sound suppression performance than the Sandman-Ti.
The Sandman-L is marketed to be durable and is advertised to not have any restrictions on barrel length; therefore it may be used with aggressive semiautomatic and automatic firing schedules. There is no titanium used in the Sandman-L construction. Despite the extreme durability rating, the designers of the silencer rate the system for pressures generated by cartridges up to 300 Winchester Magnum and not a higher pressure rating (300 Remington Ultra Magnum, for example). It is postulated that the reduction in rating is due to the Keymount system limitations. Therefore, PEW Science encourages the user to contact the silencer designer prior to use with high power magnum rifle cartridges. This caution may not be intuitive to some users due to the Sandman-L being marketed as a machine gun silencer. The Sandman-Ti, a direct-thread silencer, is rated for 300 Remington Ultra Magnum, and may be a more appropriate choice for users seeking to suppress magnum rifle cartridges.
In this review, the Sandman-L 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.
