SSS.8.1.11 - Suppressed .45 ACP Pistol Hazards - KAC and B&T MK23 Silencer Hazard Map Brief
/KAC MOD.MK23/USP and B&T Impulse-IIA SD Mk23 Rev.03 on the HK MK23 Full-Size Semiautomatic Pistol - Hazard Maps
This Silencer Hazard Map Brief documents the free field blast overpressure hazards from the KAC MOD.MK23/USP and B&T Impulse-IIA SD Mk23 Rev.03 silencers fielded on the HK MK23 semiautomatic combat handgun firing Speer Lawman 230gr .45 ACP ammunition, as evaluated in technical Report 6.214 and as tabulated in record numbers 7.1.242 and 7.1.243 in the Rankings, respectively.
The average Suppression Rating hazard contours at 1.6 m silencer end cap elevation from the instrumented blast test of the KAC MOD.MK23/USP silencer computed with the PEW-SOFT HD Blast Hazard Prediction Tool are shown in Figure 1. Hazard contours for the B&T Impulse-IIA SD Mk23 Rev.03 silencer are shown in Figure 2. The Suppression Rating hazard scale is shown in Figure 3. Ground-truth anchored Suppression Ratings from the technical reports are annotated 1.0 m left of the end cap (SR_muzzle) and 6 inches right of the shooter’s right ear (SR_ear) in both figures. Computational parameters and blast overpressure hazard field observations are provided below.
8.1.11.1 PEW-SOFT HD Computational Model Parameters
PEW-SOFT HD code Version 2.2.6 Alpha was used.
Contour elevation is 1.6 m above grade. No reflecting surfaces, other than the ground, are present in the model.
Grid resolution is 0.076 m (3 in).
The average semiautomatic jet stability index sigma_sa of the KAC silencer is 0.42. The B&T silencer has a lower jet stability index of 0.27.
8.1.11.2 KAC and B&T MK23 Silencer Models Suppression Hazard Map Observations:
The KAC and B&T silencers are designed for use with the HK MK23 weapon system. The blast load input amplitude into the silencers may be considered moderate as the barrel length of the MK23 is almost 6 inches long (5.87-in). Blast load output from the KAC silencer is lower severity and more focused and controlled than from the B&T silencer. Personnel risk in the forward field is generally more severe with the B&T silencer. Its lower stability index most likely results from its less refined baffles, as described in the technical test report referenced above and in the figures.
Hazard field severity near the operator is also more intense with the B&T silencer when compared with that of the KAC silencer. This is due to elevated blast loads as well as mechanical shock and resonance components of the system. The piston design and system mass of the KAC system possesses an elevated degree of inherent damping.
Both silencer models provide relatively consistent hazard fields after the first shot. Relative first shot severity from the B&T model is more severe than that from the KAC model.
fig 1. KAC MOD.MK23/USP HK MK23 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
fig 2. B&T Impulse-IIA SD Mk23 Rev.03 HK MK23 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
Fig 3. PEW Science Suppression Rating Scale
