SSS.6.42 - Research Supplement: Balancing Back Pressure and Suppression Rating (Article Preview)

Dead Air Sandman-S, CGS Hyperion K, Surefire SOCOM762-RC2, and OSS HX-QD 762 on a .308WIN Bolt Action Rifle with 20-inch Barrel

Four silencers evaluated by PEW Science are included in this members-only Research Supplement to examine relative First Round Pop (FRP) and overall sound signature suppression performance characteristics. The silencers in this group were selected for their ability to balance sound suppression and flow restriction (back pressure); silencers maximizing their PEW Science Suppression Rating (Figure 1) while minimizing their PEW Science Omega Back Pressure Metric (Figure 2). These silencers all possess characteristics allowing them to keep flow restriction to a minimum while still keeping sound suppression above a minimum threshold.

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Fig 1. PEW Science Suppression Rating Scale

This is not an exhaustive list of so-called low back pressure rifle silencers on the current market, but is a relatively varied representation of available current technology in the size and weight regime of interest that also balance sound suppression. The published public Sound Signature Reviews of these four silencers, with supersonic ammunition, are linked below:

• Dead Air Sandman-S (6.11)

• CGS Hyperion K (6.28)

• Surefire SOCOM762-RC2 (6.26)

• OSS HX-QD 762 (6.41)

Sound suppression and back pressure characteristics of centerfire rifle silencers typically influence their use when fielded on semiautomatic and automatic small arm weapon systems. For many types of autoloading weapons, silencer back pressure performance characteristics are paramount to the user due to the influence of this flow restriction on weapon function. Often times, a host weapon system can be adjusted or tuned for adequate function when additional flow restriction is introduced. However, for some weapon systems, this is either not possible or logistically unacceptable for the operator or armorer.

By their very nature, firearm silencers restrict gas flow to reduce sound signature; the performance trait of sound suppression being a significant performance factor. Though not the most important performance characteristic for all operators, sound suppression performance is desired by many. Purposely and effectively balancing gas flow restriction and sound suppression, by employing a variety of energy dissipating techniques within the silencer body, is relatively uncommon in today’s centerfire rifle silencer market.

Fig 2. PEW Science Silencer Relative Back Pressure Metric, Omega, For 30 Caliber Rifle Silencers

To further complicate this balanced performance requirement, the systems must also be able to exhibit adequate sound signature suppression of the first shot during many engagements. FRP is therefore also a metric of interest. Minimizing a drop in flow velocity to create less flow restriction, while still minimizing the propagation of ancillary FRP combustion, is a challenge.

This research supplement is intended to provide more information to PEW Science members with regard to specific sound signature characteristics of the tested configurations in the aforementioned reviews and to help frame objective loudness comparisons between the four low back pressure silencers in the FRP and total sound signature suppression regime. This supplement is part of ongoing PEW Science small arm weapon system sound signature research.

The full version of this article is only available to members. 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. Thank you for your support!