SSS.8.1.25 - Suppressed Bolt Action Magnum Rifle Hazards - FOR Systems Predator 6.5 Silencer Hazard Map Brief

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FOR Systems Predator 6.5 on a 20-in Barrel 6.5 PRC Bolt Action Rifle - Hazard Map

This Silencer Hazard Map Brief documents the free field blast overpressure hazards from the FOR Systems Predator 6.5 rifle silencer fielded on a 20-in barrel 6.5 PRC bolt action rifle firing Hornady ELD 147gr 6.5 PRC ammunition, as evaluated in technical Report 6.228 and as tabulated in record number 7.1.263 in the Rankings.

The average Suppression Rating hazard contours at 1.6 m silencer end cap elevation from the instrumented blast test of the Predator 6.5 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.

8.1.25.1 PEW-SOFT HD Computational Model Parameters

  1. PEW-SOFT HD code Version 2.2.7 Alpha was used.

  2. Contour elevation is 1.6 m above grade. No reflecting surfaces, other than the ground, are present in the model.

  3. Grid resolution is 0.076 m (3 in).

  4. The average bolt action jet stability index sigma_b of the silencer is 0.27.

8.1.25.2 FOR Systems Predator 6.5 Suppression Hazard Map Observations:

The FOR Systems Predator 6.5 silencer is a hybrid design with high early time flow rate and extremely low late time flow rate, resulting in relatively controlled blowdown.  Blast load into the silencer in this test is high amplitude and long duration from the 6.5 PRC short-action magnum cartridge.  The same 20-in barrel length is used in this testing as in the .308 bolt-action rifle testing.  Output jetting from this silencer is relatively stable given the combustion regime. 

Forward field severity is low compared with that from competing 7.62 NATO systems of similar size.  There is a pronounced high risk area propagating rearward from the silencer due to internal combustion severity being high from the 6.5 PRC cartridge.  Severity in the rear field near the operator is relatively low and bolt action weapon system operator hazards are similar to that generated by high performance .30 caliber silencers on the .308 bolt-action system.  Forward field dispersion from silencer jetting is relatively controlled as a result of the relatively high Omega Metric.

The hazard field from the Predator 6.5 system is consistent from shot to shot, post-FRP.

fig 1. FOR Systems Predator 6.5 20-in barrel 6.5 PRC Bolt-Action 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