M 50 Onhos tactics
From: Landing Force Bulletin #23 Employment of the Antitank Battalion (LFB23) USMC 1959
Typed in by 1JMA member WWT
601. INFLUENCES OF EMPLOYMENT
a. The employment of Ontos is influenced by its capabilities and limitations.
Employment is primarily defensive in nature.
a. Purpose. The success of antitank tactics depends largely on preparation
for action. Time permitting, extensive and detailed reconnaissance, including
reconnaissance by air, is carried out by the antitank battalion, company,
and platoon commanders.
Reconnaissance results in the selection of primary, supplementary, and
Since tanks may attack in mass, it is necessary that they be met with massed fires. Accordingly, Ontos should be employed in a manner which will permit the weight of the defensive effort to be placed in the path of the approaching attacks. This ability to achieve mass is influenced largely by the quality and timeliness of intelligence upon which a decision can be made to move sufficient Ontos units to positions of advantage.
a. Local security
Battalion or company sized AT units are capable of maintaining their own local security. However individual Ontos crews are incapable of providing the required degree of local security against infiltrating enemy infantry. Other units in the area should assist in maintaining local security. Assistance is critical when AT units occupy positions on the flanks or forward of the advancing troops or forward of the battle position of defending troops when they are in a defensive position. When so deployed, extensive illumination and preplanned protective fires may be required.
b. General security measures
An AT unit must exercise the same security measures, such as camouflage, use of obstacles, and observation of hostile ground and air attack, as other tactical units. Ontos must at all times be prepared to take evasive action and passive defense measures if attacked by air.
c. Protection against nuclear weapons
An Ontos provides some protection to its crew against the effects of a nuclear explosion. The Ontos is a relatively hard target, but it may be dismantled, thrown, or rolled along the ground by severe blast effects from a nuclear explosion. There should be no loose material or equipment in the vehicle which might fly around and cause injuries. Buttoned up, the Ontos gives protection against thermal radiation. However, combustible material should be removed from the outside of the vehicle to prevent external fires. The Ontos also affords a small degree of protection against prompt nuclear radiation.
The probability of achieving a first round hit is slightly greater when firing a two-round salvo as compared to firing a single round. This gain in first round hit probability must be considered against rapid expenditure of loaded rounds and the more frequent requirement for reloading. Salvo firing of more than two rounds will not materially increase the hit probability. In two-round firing, the order set forth in subparagraph 301a(2) is recommended to maintain turret balance. As a general rule, single round firing is used against stationary targets. Two-round salvos are desirable at the longer ranges against moving targets.
a. The disparity between the armor and armament of a tank and that of an Ontos is an important factor influencing Ontos tactics in attacking armor. This factor emphasizes the importance of taking maximum advantage of cover, concealment, alternate firing positions, and the elements of surprise and mass. Exchange of fire with tanks from exposed positions should be avoided when practicable.
b. Ontos distribute their fire among the attacking tank units, destroying or immobilizing as many as possible. The primary objective is to stop a large number of tanks, not to demolish a few. Once stopped, tanks can be dealt with at any time by a wide choice of weapons. Ontos are positioned and employed to stop tanks as far forward of friendly positions as possible.
c. Immobilization of a tank is usually easier to accomplish than total destruction. Total destruction frequently depends on penetration of heavy armor while immobilization can be achieved by attacking the highly vulnerable suspension system.
ENGAGEMENT OF POINT TARGETS
When engaging point targets such as bunkers and pillboxes, Ontos should fire from concealed, hull-defiladed positions when possible. The Ontos should not accompany the infantry in closing with the enemy. It delivers supporting fires on vital targets from positions to the rear or flanks of the infantry.
SUPPORT OF OFFENSIVE OPERATIONS
During offensive operations Ontos are employed primarily as antitank weapons. However, other capabilities of the weapon may be exploited.
a. Antitank missions
Attacking infantry are followed by antitank units prepared to counter enemy armored attacks. Routes of advance and firing positions are selected prior to the attack and are reconnoitered and occupied as soon as possible after they are uncovered by the infantry.
1) Positions should by improved and camouflaged immediately upon being
b. Fire support
The Ontos can be used in the assault gun role and is capable of rendering fire support against pillboxes and bunkers. When Ontos are so employed, maximum advantage should be taken of concealment, hull defilade, and alternate positions. Concurrently, Ontos must be available, as necessary, for the antitank mission. If enemy armor appears while Ontos are engaged in fire support, they are released immediately for their primary mission.
When employed in support of defensive operations, the antitank units are disposed in width and depth, Positions extend from locations well forward to those in the rear. From these positions Ontos may move into any area to oppose enemy armor.
a. Position defense
1) Security forces
When the enemy possesses armor, and the situation permits, antitank units are assigned to the security forces. Ontos employed from ambush can effectively delay enemy armor and assist the disengagement of other security forces. Antitank units supplement the tanks in the antitank role.
2) Battle position
Positions cover avenues of tank approach into, and within, the battle position. Some antitank units may be initially assigned forward positions, while the bulk of the units are held to the flanks and rear, ready to move into prepared positions to fire on enemy armored penetrations. Because of its light armor and backblast, it may be necessary for an Ontos to displace to alternate positions after firing.
3) General support
Antitank units may be assigned in general support to provide antitank protection for the division as a whole and increase the flexibility of employment of antitank means. In this case, Ontos are centrally controlled. They may be held in assembly areas, deployed laterally and in depth, and prepared to occupy previously organized positions.
b. B. Mobile defense
1) Security echelon
If used with the security echelon, Ontos employment is the same as with security forces in position defense. The Ontos, with its firepower and great mobility, lends itself ideally to use with the mobile defense. Normally, the optimum employment of antitank units is in the forward defensive area or with the striking force.
2) Forward defensive area
Antitank units supporting forces in the forward defensive positions assist in canalizing the movement of enemy armor into predetermined killing zones. There the enemy is attacked by the striking force. This is accomplished by normal defensive employment of antitank units in coordination with other supporting arms, and the fire and maneuver of infantry units.
3) Striking force
The employment of antitank units in support of the striking force is similar to that of other offensive operations. Antitank units provide antitank protection of the striking force elements while in assembly areas and while moving to contact.
The Ontos is an effective ambush weapon to attack and decisively defeat tanks from covered and concealed positions. In an ambush the requirement to hold a position or a piece of terrain is not present.
a. Vehicle ambushes are most effective when set in defiles where the
surrounding ground affords cover and concealment. The most suitable defiles
are those easily blocked at both ends. The sides of the defile should
be sufficiently impassable to prevent the enemy from escaping the killing
zone or mounting an attack against the ambush site.
Ontos are effective against enemy tanks attacking roadblocks.
a. During withdrawals and retirements, antitank units may be deployed
to cover tank approaches that threaten lines of communication to the rear.
Some Ontos may be integrated with tank or infantry elements and used in
the security forces, detachments left in contact, or rear guard.
705. MECHANIZED TASK FORCE
Composition of mechanized task forces varies with specific operations according to mission, terrain, enemy situation and units available. When considerations favor employment of Ontos, units of the antitank battalion may be assigned to the task force. During marches, Ontos move with the main body. When the task force deploys, antitank units seek positions from which they can protect against enemy armor envelopments. When the task force is static, Ontos are deployed to add depth and breadth to the antitank defense.
707 MECHANIZED PATROLS
a. The battlefield of the future will be porous, creating extensive need
for reconnaissance and counterreconnaissance. Units assigned to active
reconnaissance or counterreconnaissance missions should be mobile and
strong in fire power, since they will be exposed to many meeting engagements.
Ontos should not normally be used in offensive patrolling if tanks are
available. However, there may be instances when a reconnaissance in force
is carried out by a mechanized task force. If the patrolling unit is sufficiently
large and strong in tanks, the Ontos may be assigned to toe patrol to
lend additional antimechanized strength.
708. NIGHT OPERATIONS
The basic fundamentals involved in offense and defense at night are the same as those that prevail for daylight. However, at night the problem of control and coordination is greater, infantry and other units are positioned closer together, and movement is slower. Target acquisition and hit probability are drastically diminished. All of these difficulties can be overcome –to a degree – by skillful employment of illumination. If no illumination is available the Ontos should attack only those known or suspected point targets on which the weapons have been previously registered or laid. If an armored threat exists, illumination should be available on-call for Ontos units covering the most likely avenues of tank approach.
709. COMBAT IN BUILT-UP AREAS
Antitank units may assist the entry of rifle elements into built-up areas. They occupy positions to fire overhead or through gaps in friendly lines. During fighting within built-up areas, antitank units occupy positions outside of the city to assist in isolating the area. They prevent enemy armored vehicles from entering or leaving the city. If the far edge of the town cannot be covered by fire from positions outside the town, Ontos may be moved through town to support the attack. They are not normally used within built-up areas without close covering support by the infantry unit with which they are operating.
710. RIVER CROSSINGS
In attack of a river line, elements of the division antitank battalion are usually attached to, or in direct support of, regiments making the crossing. Platoons may be further attached, or used in direct support of, assault battalions. Antitank weapons support an assault crossing by firing on enemy targets on the opposite bank. Priority of fire is given to enemy armor and crew-served weapons. Specific target areas are assigned each weapon. Following the crossing of friendly armor, high priority is given to the crossing of antitank units. Once antitank units are on the far shore and the initial objective is seized, these units are employed the same as for any other attack.
711. ATTACK OF A FORTIFIED POSITION
a. The situation may permit employment of Ontos in the attack of a fortified
position. Ontos should be employed from covered and concealed positions
as the base of fore element to support tactical maneuvers.
712. DISMOUNTED EMPLOYMENT
a. A crew of 7 men is desirable for a ground-mounted 106mm rifle – 3 men to carry the weapon, 2 to carry the mount, and 2 ammunition carriers. A 3-man crew is adequate when the ¼ -ton truck or similar vehicle is available to transport the rifle and its ammunition. The antitank battalion is not provided with sufficient personnel for complete gun crews when all ground-mounted weapons are employed. Consequently, when such employment is contemplated, the training of personnel from other units for this purpose is necessary. The number of men the antitank battalion can furnish for each crew will vary with the situation. Three situations, in this respect, are possible in combat:
1) The Ontos are employed, with no ground-mounted rifles involved.
b. Either the antitank unit commander or the supported unit commander
may recommend or request the employment of ground-mounted rifles. Approval
for such requests rests with the division commander, or, with the supported
unit if the antitank unit is attached. Concurrence in the recommendation
for such employment by the antitank unit commander is therefore a desirable
1) Reduction of Ontos firepower.
713. EMERGENCY EMPLOYMENT
In emergency situations when tank support for friendly troops is not
available, Ontos may fulfill, to a limited degree, the landing force’s
requirement for mobile firepower and shock action.