Eight silencer configurations 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 due to their use on the HK MP5 submachine gun, and other pistol caliber carbine (PCC) platforms. The eight silencers behave differently, even despite some of them exhibiting similar performance quantified by the PEW Science Suppression Rating. Their 9mm MP5 suppression performance provides an excellent case study comparing current 9mm MP5 silencer technology.

Typically, silencers possessing a high flow rate also possess lower sound suppression performance with subsonic ammunition and potentially lower bystander suppression performance, in general. Also typically, silencers possessing a lower flow rate (higher back pressure) can reduce the level of operator protection by increasing ejection port blast. There are exceptions to these observations, and hybrid designs have the potential to exhibit high suppression performance in multiple combustion regimes while also reducing back pressure.

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 analytical test reports and to help frame objective loudness comparisons between eight 9mm suppressors that use various technologies to suppress 9mm weapon signatures. Both FRP and total sound signature suppression regimes are examined. This supplement is part of ongoing PEW Science small arm weapon system sound signature research. PEW Science thanks you for your support.