[194] Many of these targets were CCF choke points, dumps, and weapons emplacements. Targets were identified and confirmed by a highly developed system that employed air spotting, aerial photographic interpretation, artillery evaluation, and POW interrogation. Mortars (4.2-inch) of the 1st Marines contributed heavily to the defense of the outposts. Operations reached a peak on 12–13 August when, in a 24-hour period, Captain Carl H. Benson’s mortar company fired 5,952 rounds--4,084 high explosive and 1,868 illuminating. In addition to their defensive fires, these hard-hitting weapons attacked Chinese mortars, automatic weapons, defensive positions, and troop formations with deadly accuracy. No less precise and lethal were the fires of Captain Gene M. McCain’s gun tanks (Company C, 1st Tank Battalion), and the battalion flame tanks. Three of the latter had fired their 105s in support of the KMC on the morning of the 9th before the vehicles received orders to move east to join Company C temporarily. On the next day, 90s fired on enemy bunkers, observation posts, and trenches in the vicinity of Siberia and Stromboli. During 11 August, two gun tanks blasted at targets immediately beyond Siberia and others to the west of that outpost. Towards the end of the 11th, the critical part of Bunker battle began for the tankers also. Those elements of Lieutenant Colonel John I. Williamson’s battalion supporting the diversion and the subsequent main attack pulled into positions south of Hill 122 on the MLR and to the right in the Company F sector. It was not until the next day that the tanks operating with the 1st Marines reached a peak in gun support for the Bunker fight. Beginning with the defense of Hill 122 from 1600 that day, and for the next 26 hours, the tankers placed 817 shells on targets effecting the Chinese capability of capturing Bunker and Stromboli. In addition to the heavy ammunition, the Company C tanks, augmented by the 1st Marines antitank platoon and five tanks from the division tank reserve, fired 32,000 rounds of .30 caliber machine gun ammunition.