The incident with the snipers pointed out the advantage of having 106mm recoilless rifles on the hills. Unlike the artillery pieces at Khe Sanh, the 106mms were used in a direct fire role and because of their extremely flat trajectory, they could be employed when attack aircraft were in the target area. Another feature which endeared these weapons to the Marines was their extraordinary accuracy. The recoilless rifles were used with great finesse, especially against the well-camouflaged enemy gun positions which ringed the outposts. In most cases, it required minute adjustments to put a round squarely on target and knock out these emplacements. This was evident in one instance when a 106mm on 881S was used to silence an NVA 12.7mm machine gun which had been spraying Marine helicopters. The automatic weapon was situated inside the mouth of a small tunnel which had been cut deep into the side of a hill located north of the Company I, 3/26, perimeter. The tiny aperture, which faced south, restricted the gunner's fields of fire but that was no drawback because he only concentrated on the resupply choppers as they hovered over the Marine positions. On the other hand, the small opening prevented the gun from being knocked out by anything except a direct hit from the front. Once the men on 881S had pinpointed the heavily camouflaged site, they went to work with their 106mm. Out of necessity, their firing routine was erratic; the gunners cranked off a round, dived for cover when enemy mortars responded, jumped up, adjusted the weapon, and fired again. While spotters guided them with such unorthodox jargon as "Right a tad," or "Up a hair," the gunners repeated the process and slowly closed in on the enemy position. Finally, one glowing round disappeared completely into the side of the hill and a split second later there was a muffled explosion from deep within. Smoke belched out the mouth of the tunnel and the NVA machine gun was no more. This performance was repeated several times during the battle with the same results.(169)