The enemy's failure to silence Lieutenant Colonel Hennelly's batteries was a big point in favor of the Marines. While American news reporters gave wide coverage to the number of shells falling on the base, they frequently neglected to mention that 1/13 answered each enemy round with 10 of its own. Throughout the battle, 1/13 cranked out 158,891 mixed rounds in direct support of the 26th Marines. The methods employed by the FSCC were reminiscent of those used in World War I. Time On Target (TOT) by massed batteries, Harassment and Interdiction (H&I) by battery volley instead of a single piece, artillery boxes, rolling barrages, and battery zones were a few techniques adopted by the FSCC which more than lived up to its motto: "Be Generous."[59] [(154)]
Since the enemy did most of his maneuvering under the cover of darkness, that was when the Marine and Army batteries were the most active. Captain Baig, who wore one hat--Target Intelligence Officer--in the S-2 section and another--Target Information Officer--in the FSCC later described a good night's work:
An average night's pattern of pre-planned fires was as follows: Combined TOTs from 9 batteries (4-6); separate battalion TOTs (Army 4-6, Marine 10-15), battery multiple volley individual missions (40-50); battery H&Is (20-30). Normal 1 gun, 1 round H&Is were not used; this type of fire was of little value. Marine and Army artillery were employed in target areas and at ranges to reduce to a minimum check fires caused by the arrival of TPQ and reconnaissance aircraft. Later, as we learned finesse, air was given the targets south of the base and west of the maximum range of the 175mm guns; 1/13 was given any targets whose range required a maximum ordinate of less than 14,000 feet (altitude of TPQ run); and the 175mm guns were assigned targets to the north, northwest, and east of the base. Such were the pre-planned fires.[(155)]
A 105mm howitzer of 1/13 lashes out at NVA troops surrounding Khe Sanh. The artillery battalion was in direct support of the 26th Marines. (USMC Photo A190832)
The 175mm guns of the 2d Battalion, 94th Artillery, USA were in general support of the Khe Sanh garrison. This gun was located at Camp J. J. Carroll. (USMC Photo A190709)
In addition to volume, reaction time was a key factor. Unless friendly aircraft in the target area necessitated a check fire, artillery response was immediate--no matter what the weather. To test the proficiency of the Fire Direction Center and the gun crews, Colonel Lownds periodically walked into the FSCC bunker, pointed to a spot on the huge map which adorned the wall and directed Lieutenant Colonel Hennelly to hit it. The coordinates were quickly sent to the FDC where they were either fed into the FADAC computer or worked out manually and the firing data was then passed on to the gun crew. After adjusting the tube, the gunners slammed a round home and sent it on its way. The entire process usually took less than 40 seconds. This "instant artillery" constantly hampered enemy movement within the TAOR and helped break up numerous attacks.[(156)]
The defensive fire plan adopted by the FSCC was separate from and not to be confused with the final protective fires employed by the defenders who manned the perimeter. The artillery batteries were used to prevent the enemy assault forces from reaching the wire and to cut off the lead elements from reinforcements. The fact that the North Vietnamese usually attacked with their battalions in column made it somewhat easier for the FSCC to isolate the assault elements from the reserves. When the enemy launched his attack, the FSCC placed a three-sided artillery box around the lead battalion; three batteries of 1/13 executed this mission. The fourth battery then closed the remaining side, which faced the friendly positions, with a barrage that rolled from one end of the box to the other--much like a piston within its cylinder. The NVA force in the box could not escape and could not avoid the rolling barrage. Those North Vietnamese who spilled out of the open end of the box were subjected to the final protective fires of the Marines along the perimeter.