SSS.8.1.19 - Suppressed AR-15 Rifle Hazards - JK Armament PRO-KOR 556K Silencer Hazard Map Brief
/JK Armament PRO-KOR 556K on the MK18 5.56x45mm 10.3-in Barrel Automatic AR15 Rifle - Hazard Map
This Silencer Hazard Map Brief documents the free field blast overpressure hazards from the JK Armament PRO-KOR 556K rifle silencer fielded on the 10.3-in MK18 AR-15 semiautomatic rifle firing M193 55gr 5.56 NATO ammunition, as evaluated in technical Report 6.222 and as tabulated in record number 7.1.253 in the Rankings.
The average Suppression Rating hazard contours at 1.6 m silencer end cap elevation from the instrumented blast test of the PRO-KOR 556K silencer computed with the PEW-SOFT HD Blast Hazard Prediction Tool are shown in Figure 1. The Suppression Rating hazard scale is shown in Figure 2. Ground-truth anchored Suppression Ratings from the technical report are annotated 1.0 m left of the end cap (SR_muzzle) and 6 inches right of the shooter’s right ear (SR_ear). Computational parameters and blast overpressure hazard field observations are provided below.
8.1.19.1 PEW-SOFT HD Computational Model Parameters
PEW-SOFT HD code Version 2.2.7 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 silencer is 0.15.
8.1.19.2 JK Armament PRO-KOR 556K Suppression Hazard Map Observations:
The JK Armament PRO-KOR 556K silencer is a hybrid design with high early time flow rate and relatively controlled late time flow rate that focuses the blast field forward. Blast load input into the silencer is relatively high amplitude from the 10.3-in rifle barrel. Blast load output from the silencer is moderately controlled from its distal vent arrays.
Near-field severity forward of the operator is relatively high but comparable to other high distal flow rate suppressed MK18 systems. Near the operator, risk increases and is driven by ejection port blast hazards. Adjacent to the weapon system and operator, risk is reduced. The early time flow rate from the silencer is high enough such that ejection port blast hazards are reduced. Further hazard reduction may be possible through weapon tuning.
The hazard field from the PRO-KOR 556K system is relatively consistent, from shot to shot. Blowdown momentum is mostly controlled, post-FRP.
fig 1. JK Armament PRO-KOR 556K 10.3-in MK18 AR-15 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
Fig 2. PEW Science Suppression Rating Scale
