The 82nd Jungle Fighting
Chemical Mortar Battalion

by Jack Butler

Editor's note: Jack Butler, a lieutenant in WWII, was platoon leader of the 2nd platoon, Co C, 82nd Cml Mortar Bn, during its combat service in the Pacific Theater. Now retired as a lieutenant colonel, Jack wrote this account in 2000. The two references to "Gailey" are to the book Bougainville: The Forgotten Campaign 1943-1945, by Harry A. Gailey, Kentucky: The University Press, 1991.

The old 4.2 inch M2 mortar of WWII was a portable weapon! Later models sacrificed this valuable feature for increased range and thereby greatly limited its flexibility for jungle fighting.

The Second Battle of Bougainville, Northern Solomon Islands (the BIG one - battle and island) in March 1944 saw the 4-deuces employed for the first, and likely the last time, in heavy jungle cover. Portability was the feature that made possible the successful use of this uniquely suited weapon. Weighing, in total, 333 lb. and breaking down into three loads, it was carried where even the 2-wheeled cart could not traverse. The baseplate, at 175 lbs., was the heaviest, usually a 2-man load, although one of the troopers in the 2nd platoon, Co. C, 82nd CMB, gained the nickname "Baseplate" for frequently grabbing it by the extended handles and throwing it across his back. His last name was Saxe and he was from South Dakota, a great bear of a man. Saxe would give his pack and carbine to another squad member, get that BP across his shoulders and move out in almost any terrain. The barrel, at 105 lbs., was another 2-man load, though often one big trooper or another would get it on his shoulder and move it into the jungle. A 53-lb. standard was a "piece of cake" for the average soldier.

Certainly, the 6x6 2-1/2 ton trucks were used to move mortars and ammunition as far as possible on existing trails, from which point the carts were employed to their maximum advantage. Considering the "situation and the terrain" on Bougainville, there was very limited penetration of the jungle by wheeled vehicles and tanks fared not much better. The island still has an active (smoking) volcano in Mt. Bagana, the earth is covered in a deep bed of volcanic ash and forested between the narrow beaches and the mountain ranges by Banyan trees that have many aerial roots that develop into additional trunks. At its base, a typical tree would cover an area 8-10 feet in diameter. The terrain described here is inland from the landing beaches on Empress Augusta Bay in the south central portion of this 125-mile stretch of island, 30 miles wide, south of the bay.

Gailey describes the beachhead as "a maze of swamps, rivers, and rugged hills overgrown with jungle." This is western Bougainville. The southwestern and eastern parts of the island have the best harbors and, especially in the east, moderately broad plains, which widen to over ten miles near the village of Numa Numa. In contrast, "western Bougainville is characterized by many mountain streams, which carry much silt downstream. The silt gradually blocks the flow of water, creating wide swampy areas adjacent to the coast, which extend inland over a mile in places. ... The geography was one major reason that the Japanese discounted the possibility of invasion from the west and concentrated their troop strength in the south." [Gailey, pp. 34-5]

Portability and Ingenuity enabled the troops to occupy key positions from which to deliver thousands of rounds of HE, significantly contributing to the destruction of the Japanese in their March, 1944 suicidal thrust to retake the beachhead and capture the airfields therein. Fields of fire had to be cut in dense jungle with a canopy that kept sunlight from reaching the ground. To this end, each squad was equipped with a 2-man crosscut saw and each platoon was well supplied with composition C, primacord, detonators, a hand brace with a supply of augers. No doubt the Navy Seabees, the Army Engineers and the Ordnance Corps made great contributions. The diameters of the trees and their huge blades (roots) that extended far out from the trunk made it necessary to use the OVM axes from the trucks to cut steps into the blades so two men could get to the trunk and wield their crosscuts to weaken the tree. This would be done on several of the larger trees. Above the cuts would be bored holes, one per tree, deep enough to hold a quarter pound stick of composition C (looked like a stick of peanut butter) and a detonator in three or four larger trees. The remaining trees to be topped were wrapped in a continuous belt of primacord. With telephone wire run back a safe distance and all personnel clear of the area, the cry "Fire in the Hole" signaled the plunger to be depressed. The tremendous explosion of composition C and primacord opened the sky for safe passage of 4.2 inch shells. One falling tree brought down several of its neighbors.

It should be noted that, with all those fallen trees, there remained much work to make a suitable firing position. At that time we had six tubes to a platoon, which required about 50 yards of lateral clearing, plus sufficient room in front of each gun for aiming stakes.

Portability and Accuracy became even more significant features in the months after the remaining Japanese fell back into the jungle on the high ground. XIV Corps took the offensive to establish an outpost line roughly paralleling the semi-circular beachhead. This was part of the preparation for relief of XIV Corps by the Australian II Corps to enable XIV Corps to participate in the Sixth Army invasion of Luzon, PI in January 1945. With more than thirty thousand men, the Australian force was deemed adequate to continue General Griswold's concept of keeping the Japanese under surveillance and defending the beachhead against any counterattack that might threaten the airfields, in accord with General MacArthur's overall strategy of letting the Japanese "wither on the vine." [Gailey, pp. 191]

Involved in establishing the outpost line, the 82nd CMB moved out to firing positions inaccessible by any wheeled or tracked vehicles. One example was the 2nd platoon, Co. C, occupying a position on the near bank of a mountain stream only with the aid of New Guinea natives as porters. These short, dark-skinned people, men and women, were part of a labor battalion led by an Australian sergeant all of whom conversed in Pidgin English. Each one of them was capable of carrying sections of the mortar and boxes of ammunition up a very steep incline to the stream. The OP for this action was across the stream and up a still steeper climb to the crest. From the OP, 4.2s supported patrols along the forward and reverse slopes.

One mission involved neutralizing a sniper post in the remains of a Banyan tree that had been shattered and burned by previous infantry mortars and flamethrowers. One or more Japs had burrowed into the base of the tree and may have dug upward into the tree, a technique previously used in the 37th Division sector that was combatted by running a long hose from a fuel truck, pumping in several gallons of gasoline, then igniting the gas.

In this action, a patrol from 129th Infantry Regiment was returning up the reverse slope when a sniper killed a soldier carrying a Browning Automatic Rifle (BAR), a target for which snipers would lie in wait. The patrol was able to return sufficient rifle fire to retrieve the body, but the BAR had fallen downhill close to the tree. The 4.2 observer was asked to neutralize the weapon and the tree, both of which were clearly visible from the OP. Having previously registered on the tree, it took only a small adjustment to drop one HE round that destroyed the BAR. Two more rounds from the same tube, using delayed fuzes, scattered the tree and its occupant(s) mostly downhill. The patrol leader, Lt. Hall, was so impressed he requested and was granted transfer to Co. C, 82nd CMB. Unfortunately, he lost a leg in his first action on Luzon.

To offer comment, additions or corrections to this account, send e-mail to the author, Jack Butler, at

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