92nd ARMORED FIELD ARTILLERY BN
SFC George T. Powell (Battery C chief of detail), anxious about some new men who had never seen combat, took off toward their section of the main battle line. When he arrived at the nearest halftracks, he found his men already manning the machine guns. Several others were setting up a machine gun on a ground mount. No longer anxious, Powell relaxed and began to enjoy the battle. Several other friendly machine guns were already in action.
SFC Willis V. Ruble, Jr. (Headquarters Battery motor sergeant), who at first thought the noise was caused by someone throwing wads of ammunition into the fire, ran for a halftrack and unzipped the canvas cover on a caliber .50 machine gun while several slugs whistled past, and he then looked about for a target. He saw four or five persons in the field in front of Battery A's positions. They were wearing dirty white civilian clothes and Ruble thought they were South Koreans until he saw one of them carrying a rifle. He fired three short bursts, knocked one of them down, spun another one around. Just then he noticed flashes on the hill in front. Figuring that the small-arms fire could take care of the enemy troops close in, Ruble turned his machine gun toward the distant flashes.
SFC James R. White (Battery A) remembered only being at a machine gun on a halftrack but did not know how he got there. By this time, a minute or two after the first shot had been fired, enemy fire was so intense that tracer bullets formed a thin red arch between the battalion's position and Hill 200, from which most of the enemy long-range fire came. The ammunition belt in White's machine gun was crossed. White was shaking so badly that he could not get it straightened, and he was afraid to expose himself above the ring mount. After a bit, he stood up, straightened the belt, and began firing.
The battalion executive officer (Major Tucker), who had started out to inspect the
perimeter soon after the firing commenced, opened the rear door of White's halftrack and cautioned him and several other men in the vehicle to pick targets before firing. White then waited until he saw the location of the enemy machine guns before he fired. Visually following the tracers back toward the hill, White was able to locate an enemy emplacement. He opened fire again. He could see his own tracers hitting the hill, so he walked his fire in on the enemy position, then held it there until his belt gave out. White then reloaded his gun with a fresh belt (105 rounds) but did not fire at once. The man firing the caliber .30 machine gun on the same halftrack was playing it cool; he was firing in short bursts at enemy in a field across the road.
Within ten minutes or less the exchange of fire had become a noisy roar. Enemy bullets cut up the telephone wires that were strung overhead, forcing the battalion to rely on its radios.
Captain Raftery stood in the middle of Battery C's area trying to determine enemy
intentions. The bulk of enemy fire against the battery appeared to be coming from Hill 200, where Raftery estimated there were six machine-gun emplacements, which the Chinese had reached by old communication trenches. As these entrenched troops acted as a base of fire, enemy riflemen took concealed positions in the cemetery while others, armed only with hand grenades, crawled toward the howitzers. Captain Raftery thought the Chinese were concentrating on his No. 5 howitzer the most vulnerable because of its forward position. Enemy fire in that area was so intense that the artillerymen could not man the machine guns on the nearest halftrack. Deciding that the enemy was trying to knock out one howitzer and blow up the powder and ammunition for psychological effect, he called the chief of No. 5 howitzer section and instructed him to pull his "tank" back into defilade and on line with Nos. 4 and 6.
Behind the No. 4 howitzer, Lieutenant Hearin tried to see what the men were shooting at. Flashes on the hill were 600 to 1,000 yards away, and it seemed unusual that the enemy would attack from so far. He looked for enemy elements coming in under the base of fire. Suddenly he noticed men of the battery running from the No. 5 to the No. 6 howitzer. Several feet behind them, grenades were bursting.
Gun sections still manned the howitzers, firing harassing and interdiction missions. The
range had decreased during the night and the cannoneers were aware of increased
machine-gun activity on the hill mass in front of the battalion.
Breakfast was ready at 0445. Chow lines formed in all batteries. First sign of daylight
appeared ten or fifteen minutes after 0500. Most of the men had finished breakfast. Most
of the pyramidal tents, used because of cool weather, were down. In Headquarters Battery only the command post and kitchen tents were standing. In Battery A the kitchen tent was still up. The communications system was still intact but commanders had pulled in most of their outlying security installations. Equipment and personnel were just about ready for march order.
Colonel Lavoie, having eaten an early breakfast, had just returned to the mess tent where an attendant was pouring him a cup of coffee. Major Raymond F. Hotopp (battalion S-3) prepared to leave on reconnaissance at 0530, placed his personal belongings in his jeep and walked over to see whether the battalion commander was ready. Capt. John F. Gerrity (commanding Battery A) was getting into his jeep to join Colonel Lavoie on reconnaissance.
An unidentified artilleryman from Battery C, with a roll of toilet paper in his hand, walked toward the cemetery in front of the howitzers. As he approached the mounds in the graveyard, he saw several Chinese crawling on their bellies toward his battery. Startled, he yelled, threw the toilet paper at an enemy soldier, turned, and ran. The Chinese soldier ducked involuntarily. At that moment, someone tripped a flare outside the perimeter. Capt. Bernard G. Raftery (commanding Battery C) looked at his watch. It was 0520.
Machine guns opened fire. At first many thought someone had accidentally tripped a
machine gun, since the marines were supposed to be in front of the artillery positions. But when the firing increased there was no more doubt. Men in the mess line scattered for cover. Major Hotopp dropped to the ground and dived under a halftrack. SFC Charles R. Linder (chief of section), warming his feet over the running "tank" motor,  jumped off and took cover behind the vehicle. Most of the men took cover wherever it was most
Colonel Lavoie saw a bullet hole suddenly appear in the side of the mess tent. He ran
outside. "Man battle stations!" he yelled, "Man battle stations!" and headed for his
command post tent to get into communication with his battery commanders.
Captain Raftery looked at Lt. Joseph N. Hearin (Battery C executive). "This is it!" he said,
scrambling to his feet. "Let's go!" He and Hearin got out of their command post tent at the same time.
However, Major Tucker did establish a complete system of security outposts with
trip flares ahead of the outposts, a complete telephone communication system, and a radio net as an alternate means of communication. He had laid out the main battle line but only a few positions were dug in at darkness. There was no defensive wire, demolitions were not out, nor had the men dug in and sandbagged such critical installations as the fire direction center and the communications center. These tasks had a lower priority and usually waited until the second or third day of the process of developing the battalion perimeter. 
Members of outpost detachments ate chow early and went to their halftracks or
ground-mounted machine-gun positions before dusk in order to be familiar with their
sectors of responsibility, fields of fire, and to check their communications. Thereafter,
except for relief detachments, no traffic was allowed to the outposts or beyond the
battalion perimeter. Colonel Lavoie wanted security guards to heed and challenge all
movement or activity. Four to eight men manned each security outpost, half of them being on duty at a time. Colonel Lavoie inspected the perimeter defenses just before dark, pointing out to his men the Marine positions on the hill to the front. 
That night the battalion reinforced the fires of the 1st Marine Division. Corps Artillery
headquarters called about 2100 with instructions for the 92d Field Artillery Battalion to
prepare to remain in its present positions for several days. Colonel Lavoie promptly called the 11th Marine Regiment (an artillery unit) he was to reinforce and asked for further instructions. Wire sections laid telephone lines to the 11th Marines, completing the job at 2300. Midnight passed and all was quiet. At 0115 the Marine regiment telephoned asking Colonel Lavoie to report immediately to its headquarters. When Lavoie arrived there, the Marine commander outlined a new plan. The 1st Marine Division, its entire left flank exposed, planned to withdraw soon after daylight on 24 April. Colonel Lavoie was to keep his howitzers in firing position until the last moment, but to be prepared to move at 0530. Battery A, 17th Field Artillery Battalion, with its heavy, towed howitzers, was to leave at 0400.
At 0230 Colonel Lavoie returned to his command post. Although he was very tired, he
could not sleep and scarcely had time for it anyway. He reviewed the displacement plan, being particularly concerned about getting the 8-inch howitzers on the road at 0400. Battery commanders were called at 0315, and Colonel Lavoie gave them the complete plan and order for the move. He instructed his commanders to serve a hot breakfast.
The heavy howitzers moved out on schedule. At the same time guards were going through the battalion area waking all personnel. Within a few minutes there was the sound of trucks moving about and the usual commotion that goes with the job of getting up, packing equipment, striking tents, and loading trucks all in the dark.
Putting his entire battalion on a man-battle-stations basis, Colonel Lavoie and his staff officers tried desperately to collect stragglers and stop the withdrawal, but the momentum was too great by the time the soldiers reached Colonel Lavoie's battalion and most of them continued determinedly on. 
When morning came on 23 April the Chinese, in possession of a threemile-deep corridor
west of the 1st Marine Division, turned to attack the Marine left flank. They completely
overran one ROK artillery battalion and the 2d Rocket Field Artillery Battery, both of
which lost all equipment.  The 987th Armored Field Artillery Battalion, partially
overrun, lost some. 
Colonel Lavoie's 92d Field Artillery Battalion (a self-propelled 155-mm howitzer unit)
moved back battery by battery to a new position near the Pukhan River south of
Chichon-ni. Batteries registered as soon as they were laid.
Battery C, in position north of a trail-size road through the new battalion position, placed
its howitzers on the reverse slope of an incline that offered defilade. Battery A and
Headquarters Battery were in a rice paddy south of the road with Battery A, 17th Field
Artillery Battalion. Battery A of the 17th was an 8-inch howitzer outfit temporarily
attached to the 92d Field Artillery Battalion to replace its own Battery B which, in turn,
was attached to the 17th Field Artillery Battalion. (The lower half of the map on page 165 shows the batteries' positions in detail.)
Late in the afternoon the last howitzer was laid and ready to fire. The general military
situation was tense. The artillerymen, having had little sleep during the past thirty-six
hours, were tired, but immediately went to work establishing their usual perimeter for the night. Colonel Lavoie tall, and gentle almost to the point of shyness insisted upon always having a well-fortified perimeter. Even when smiling, as he usually was, he had a way of being obdurately firm about the condition of the battalion perimeter, as he also was about standards of performance. Convinced that his responsibility as an artillery commander was to insure continuous artillery support to the infantry, he also reasoned that the very time when the infantrymen would most urgently need supporting artillery might well coincide with an enemy attack on his own perimeter. Colonel Lavoie had therefore developed a standard defensive perimeter that, from the outside toward the gun batteries in the center, consisted of patrols covering neighboring terrain; outposts, usually centered around a halftrack, for warning and delaying; a dug-in and fully manned main battle line just beyond grenade range of the battalion's critical installations; and a highly mobile reserve in the center. This reserve force usually was made up of two or three halftracks with 8 or 10 men for each vehicle.
Colonel Lavoie's acting executive officer (Major Roy A. Tucker) set up the perimeter on
the afternoon of 23 April. Because of the limited time before darkness, which came about 1745, the perimeter was not as elaborately developed as usual, nor was there time to patrol nearby terrain.
U.S. Army Document Chapter 12 "Artillery in Perimeter Defense"
* The U.S. IX Corps, near the center of the Korean peninsula, renewed an attack on 21
April 1951 to seize a line running generally from Kumhwa to Hwachon Reservoir. The
corps included only two divisions at the time the U.S. 1st Marine Division and a ROK
division. The attack went well. Both divisions, meeting no enemy opposition, gained about three miles. They encountered only scant resistance after they jumped off again on the morning of 22 April. 
Front-line units advanced two more miles on the 22d. The enemy made little effort to
interfere although, late in the afternoon, artillery and air observers reported an unusual
amount of enemy movement north of the line. 
That night the Chinese struck back with their own 1951 spring offensive, a full-scale
attack, which they labeled the "First Step, Fifth Phase Offensive." The Chinese limited
their offensive to the western half of the front lines, the eastern prong of which pointed
directly at the IX Corps' ROK division. It appeared that the Chinese had made it easy for
IX Corps troops to advance so that they, in turn, could launch their own attack when
friendly forces were extended and before they had a chance to dig in securely again. By 2000 enemy soldiers were several thousand yards behind friendly lines and were firing on artillery units that had displaced forward only that afternoon. Front lines crumbled within an hour or two. Infantrymen poured back on the double. Artillery units were forced to withdraw. 
The liaison officer from the 92d Armored Field Artillery Battalion to one of the ROK
regiments (Capt. Floyd C. Hines) radioed his battalion. "Someone's pushed the panic
button up here," he warned.
The battalion commander (Lt.Col. Leon F. Lavoie) received this message on his jeep radio as he was on the way to Corps Artillery headquarters where he intended to seek
immediate engineer help to repair and maintain the precariously narrow supply road. From other messages it was soon evident to Colonel Lavoie that the Chinese had made a serious penetration of the lines. Stopping at the first military installation he came to, he called IX Corps Artillery to report the information he had on the front-line situation, and then, because the emphasis had suddenly shifted from repairing the supply road to defending it, he turned back to his own battalion.
The 92d Armored Field Artillery Battalion, reinforcing the fires of both divisions of the
corps, had moved forward that afternoon to a point near the boundary between the ROKs and marines, a little less than half way from Chichon-ni to Sachang-ni. The road between these two villages, following a deep river gorge, was exceedingly narrow. By 2130, when Colonel Lavoie got back to his battalion, the road was jammed with vehicles and ROK infantrymen were moving back pell-mell along both sides of it.