SSS.8.1.40 - Suppressed AR-15 Rifle Hazards - JK Armament PRO-KOR 6 Mini Ti Silencer Hazard Map Brief
/JK Armament PRO-KOR 6 Mini Ti on the MK18 10.3-in and M4A1 Mid-Gas 5.56x45mm 14.5-in Barrel Automatic AR15 Rifles - Hazard Maps
This Silencer Hazard Map Brief documents the free field blast overpressure hazards from the JK Armament PRO-KOR 6 Mini Ti silencer fielded on both the 10.3-in MK18 14.5-in M4A1RIII AR-15 semiautomatic rifles firing M193 55gr 5.56 NATO ammunition, as evaluated in technical Report 6.243 and as tabulated in record numbers 7.1.288 and 7.1.289 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 silencer on the MK18 computed with the PEW-SOFT HD Blast Hazard Prediction Tool are shown in Figure 1. Hazard contours for the silencer on the M4 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). Computational parameters and blast overpressure hazard field observations are provided below.
8.1.40.1 PEW-SOFT HD Computational Model Parameters
PEW-SOFT HD code Version 2.2.8 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 on the MK18 is 0.17. On the M4, the silencer has a higher jet stability index of 0.22.
8.1.40.2 JK Armament PRO-KOR 6 Mini Ti Suppression Hazard Map Observations:
The JK Armament PRO-KOR 6 Mini Ti is a compact hybrid rifle silencer that produces efficient blast propagation control and a forward-biased hazard field on both short-barrel 5.56x45mm NATO weapon systems. On the 10.3-inch barrel MK18, blast load input amplitude into the silencer is high. Despite having a truncated first expansion (blast) chamber compared to the larger PRO-KOR 556K, the blast momentum propagation with the Mini model is still controlled to a significant degree (Fig. 1). When fielded on the 14.5-inch mid-length gas M4A1, the approximately 40 percent longer barrel reduces peak blast pressure input amplitude into the silencer, resulting in lower peak muzzle blast overpressure and impulse, shorter coupled jet duration, and faster decay of latent jetting, producing reduced hazard in the forward field (Fig. 2).
In the rear field near the operator, the risk profile shifts between the two platforms due to host weapon gas dynamics. On the untuned 10.3-inch MK18, the silencer's high early-time flow rate and strong muzzle suppression do somewhat reduce operator risk, though the smaller blast chamber volume induces slightly higher back pressure and ejection port blast than the larger PRO-KOR 556K. When moving to the untuned 14.5-inch M4A1, the lower muzzle blast amplitude and increased muzzle standoff distance are not sufficient to overcome the more severe ejection port blast generated by the over-gassed M4 host weapon. Consequently, positive phase blast momentum and peak pressure at the shooter's head increase, increasing operator risk.
The hazard field generated by the JK Armament PRO-KOR 6 Mini Ti exhibits high to moderate consistency after first-round-pop (FRP) on both platforms. While FRP momentum is less throttled after peak accumulation than with the longer K model, and FRP divergence at the muzzle is slightly more pronounced on the lower-pressure M4A1 than on the MK18, overall post-FRP blast load propagation remains stable throughout the shot string.
fig 1. Tuna Cans 5.56 XL 14.5-in M4A1 AR-15 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
fig 2. Tuna Cans WRMFZY 5.56 14.5-in M4A1 AR-15 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
