MK248 Mod 1 and A191 Sniper Rifle

MK248 Mod1 Sniper Rifle and A191 Sniper Rifle. In a high confidence environment2 the hit percentage is maximized at each range due to the uncertainties being at a minimum. In this environment, all 3 ammo types maintain a 100% hit percentage out to 800 meters, and the 230 OTM Sniper Rifle to 900 meters. At 1000 meters, the hit percentage for the A191 Sniper Rifle, MK248 Mod1 Sniper Rifle, and 230 OTM are: 93%, 96%, and 98% respectively. The 5% spread can be more or less important based on the type of analysis being done. At 1100 meters, the spread from best to worst hit probability (A191 being worst and 230 OTM being best) is 12%, and at 1200 meters the spread is 17%. At 1300 meters and beyond, the 230 OTM maintains approximately 20% advantage in hit probability compared to the A191, and 10% advantage in comparison to the MK248 Mod1 .

The ranges at which the ammo achieves a 90% hit percentage. MK248 Mod1 sniper rifle achieves 90% hit percentage 68 meters beyond A191 Rifle, and the 230 OTM Rifle pushes 90 meters beyond MK248 Mod1, which is 158 meters beyond A191. illustration of the shot patterns at 1300 meters for the 3 ammo types. At 1300 meters and beyond, there is a 10% improvement in hit percentage between all 3 ammo types. In other words, MK248 Mod1 Sniper Rifle is 10% better than A191, and 230 OTM is 10%-11% better than MK248 Mod1.

The nominal uncertainties which characterize medium uncertainty WEZ are shown in Table 2. The WEZ is somewhat limited by uncertainties considered average for trained shooters and average equipment. In this uncertainty scenario, 100% hit percentage is only maintained out to 500 meters, 600 for the 230 OTM. By 1000 meters, the hit percentage is reduced to 47%, 56% and 70% for A191, MK248 Mod1, and 230 OTM respectively. By 1500 meters, the hit percentages for the 3 ammo types are 18%, 20% and 25%.

The 90% hit percentage thresholds for a medium confidence environment are shown in Table 5. MK248 Mod1 pushes 26 meters past A191, and the 230 OTM pushes 79 meters beyond MK248 Mod1, which is 105 meters beyond A191. Below shows a graphic representation of the hit percentage on the IPSC target at 1000 meters. Note that the vertical dispersion, which is primarily determined by muzzle velocity consistency is similar for all 3 rounds. This is the effect of the 15 fps standard deviation in muzzle velocity used for the medium quality ammunition. The real difference in the shot patterns is in the horizontal plane, with the higher BC bullet having less horizontal dispersion and more shots on target in the +/- 2.5 mph wind uncertainty.

The shot patterns may not look dramatically different, but the hit percentages are quite striking. The MK248 Mod1 achieves 9% higher hit percentage than the A191, and the 230 OTM achieves 23% higher hit percentage than the A191, and 13% higher than MK248 Mod1 at this range (1000 meters).

The low confidence environment models a shooter with minimal training and shooting ability in addition to ammo of poor consistency. Details of a low confidence environment are listed in Table 2. In a low confidence uncertainty scenario, 100% hit probability is limited to 300 meters for all 3 ammo types. By 1000 meters, the hit percentage is reduced to 31% for A191, 35% for MK248 Mod1, and 41% for the 230 OTM. Under such high uncertainties, hit percentages are 1500 meters are quite low for all three ammo types. The 90% hit percentage thresholds for a low confidence environment are shown in Table 6. Table 6 shows that the 90% hit percentage is affected least in the low confidence environment, only being extended from 502 to 558 (56 meters) from worst to best ammo type. This minor increase in 90% range is due to the overwhelming nature of the uncertainties involved in the low confidence environment.

To recap; the high confidence environment allowed for a 158 meter improvement in the 90% range from the worst to the best performer, the medium confidence environment allowed for a 105 meter improvement, and the low confidence environment only nets a 56 meter improvement. This should not come as a surprise; that a highly trained shooter operating in a minimum uncertainty environment can maximize range extension from improved ballistic performance. On the other hand, in environments that have a great deal of uncertainty including lack of rangefinders, and only estimating wind with within +/- 4 mph, the improvement in ballistic performance is much less profound in terms of extending the 90% range. The overwhelming effect of lower confidence environments is a reduction in hit percentage at all ranges.

Ballistic performance related comparisons are not the only considerations to be made when assessing the suitability of various ammo types. The following sections address some of the components that are not captured in the hit percentage portion of the WEZ analysis, but are none-the-less important considerations.

Prior studies have conducted basic comparisons between A191 and MK248 Mod1 ammo types for use in the 300 Win Mag. The results of this WEZ analysis supports prior conclusions that the MK248 Mod1 is superior to A191 in supersonic range, kinetic energy, and hit percentage regardless of the uncertainty environment. In addition to verifying those findings,  an alternative bullet option (the Berger 230 grain Hybrid OTM) was assessed and found to be superior to both A191 and MK248 Mod1 by a substantial margin. The improvement in 90% hit percentage range for the 230 OTM is about the same as the improvement of MK248 Mod1 over A191. With similar terminal performance, and potential for increased barrel life, the Berger 230 grain Hybrid OTM is the clear choice for maximizing hit percentages and extending effective range of the 300 Winchester Magnum cartridge in the XM-2010 platform.