[192] BGen Frederick P. Henderson ltr to Hd, HistBr, G-3 Div, HQMC and MS comments, dtd 20 Jun 67, hereafter _Henderson ltr III_. After a sharp drop on the 14th, the artillery support gradually decreased in proportion to the amount and strength of the enemy’s action against Hill 122. By 20 August, 3/11 was firing only 244 rounds a day. Only on the 26th, during a serious Chinese attempt to retake Bunker, did the number of artillery rounds match the intensity of the fire support rendered during the earlier part of the month. It was not only the quantity of 11th Marines support that the infantry called for during the battle of Bunker Hill; quality was equally important. A majority of the more than 28,000 rounds that 3/11 fired during the eight days of Bunker Hill fell around the besieged outposts. Many rounds were fired in defense of MLR positions. In both of these types of protective fires, extreme accuracy and precision were required due to the proximity of enemy and friendly lines in order to prevent any “short” rounds from falling among Marine positions. Lieutenant Colonel Armitage recalled that during the height of the battle on the night of 12 August, “we did have a bad scare ... when Captain Connolly reported that friendly mortar fire was falling short.”[193] The battalion immediately ceased fire with its 60mms, 81mms, and 4.2s and each piece was checked; the culprit was quickly located and within 5–10 minutes 3/1 resumed fire. [193] _Armitage ltr_ and comments, p. 12. During the August battle, artillery in general support of the entire division and I Corps artillery reinforcing the fires of Colonel Henderson’s regiment, stepped up their efforts to destroy the distant and more difficult targets, including mortars and artillery. These continued to be the main cause of Marine casualties. Some of the labors of the 11th Marines gun crews did silence enemy heavy weapons, but personnel losses from enemy shellings still mounted, especially in the infantry units. To assist in the location and destruction of the enemy artillery, aerial observers spent considerable time in spotting and fixing Chinese weapons positions. Besides these counterbattery efforts, the 11th Marines employed other artillery means to provide the additional support the 1st Marine Division requested during Bunker Hill. Two of these were the counter-counterbattery and the countermortar programs, the former being a passive defense-deception program to minimize Chinese counterbattery fires against 11th Marines weapons. Nearly every day C Battery, 17th Field Artillery Battalion, fired special request missions.[194] Another type of fire, flak suppression, aided the cause of close air support pilots delivering ordnance against those Chinese positions taking Bunker Hill and Stromboli under fire. At night, illumination shells helped outpost and frontline Marines in locating groups of enemy massing for assault on Hill 122.