In November 2009, Harrison consecutively struck two
Taliban machine gunners south of
Musa Qala in
Helmand Province in
Afghanistan at a range of using a
L115A3 Long Range Rifle. In a BBC interview, Harrison reported it took about nine shots for him and his spotter to range the target, using a bracketing technique. Then, he reported, his first shot "on target" was a killing shot followed consecutively by a kill shot on a second machine gunner. The bodies were later found by Afghan National Police looking to retrieve the weapon (which had already been removed). The first Taliban was shot in the gut and the other through the side. Later in the day an
Apache helicopter hovered over the firing position, using its laser range finder to measure the distance to the machine-gun position, confirming the then record distance. In the reports, Harrison mentions the environmental conditions were perfect for long range shooting: no wind, mild weather and clear visibility. using
drag coefficients (Cd) provided by Lapua, the L115A3 has an approximate supersonic range of under
International Standard Atmosphere conditions at sea level and at the
altitude of Musa Qala. This illustrates how differences in environmental conditions can significantly affect bullet flight. The Schmidt & Bender MILITARY MK II 5–25×56mm scope used by Harrison on the L115A3 Long Range Rifle has windage and elevation adjustment of 0.1
milliradian (mil), double turn elevation turret, and parallax and illumination control. The sight has a maximal vertical elevation range of 26 mil, and the sight adjustment increment of 0.1 mil equates to a point of impact shift at a distance of . To increase the maximal elevation range Accuracy International produces mounts for telescopic sights with a 13.1 mil (45 MOA) built in vertical cant designed for their .338 Lapua Magnum rifles fitted with the 5–25×56 telescopic sight. Even with a 13.1 mil canted
mount the employed sighting system is not able to dial in over 39.1 milliradian of vertical aiming correction, which is significantly less than Harrison required during his record shot. The
external ballistics software program by JBM Ballistics predicts that the bullets of British high pressure .338 Lapua Magnum cartridges using 16.2 g (250 gr) Lapua LockBase B408 bullets fired at muzzle velocity under International Standard Atmosphere conditions at elevation assuming shooting and target positions are at equal elevation and a zero (the distance at which the rifle is sighted in) arrive at distance after approximately 6.017 seconds flight time at velocity and have dropped (in angular units 48.9 milliradian, 168 MOA) on their way. Harrison had to use the P4 reticle offering 0.5 mil spaced holdover hash marks in his 5–25×56 telescopic sight to compensate for the lack of vertical aiming correction and thus achieve the required aiming solution. The long horizontal line at 5× zoom or magnification represent 49.1 milliradian (168.6 MOA) or slightly over the required assumed vertical elevation. == Private life ==