M102 Howitzer - Basic Design

Basic Design

The 105-mm howitzer M102 is a lightweight towed weapon, which has a very low silhouette when in the firing position. The M102 howitzer fires a 33-pound projectile of semifixed ammunition and at charge 7 will fire 11,500 meters. It has a muzzle velocity of 494 meters per second. The maximum rate of fire is 10 rounds per minute for the first 3 minutes, with a sustained rate: 3 rounds per minute.

A roller tire attached to the trail assembly of the M102 permits the weapon to be rotated 6,400 mils around a firing platform, which provides the pivot for the weapon. The weapon can be elevated from -89 mils (-5 degrees) to a maximum of 1,333 mils (75 degrees). The panoramic telescope has a four power, fixed focus optical system, with 178 mils field of view. It contains dry nitrogen gas to retard fogging and condensation. The parallax shield used during boresighting protects the lens.

The trails are made of aluminum alloy. They are a single box trail in wishbone shape, and serve three purposes, which are: mobility, stability, and stowage of section equipment. The lunette is the towing pintle that allows the weapon to be connected to the vehicle. When towing, vehicle has a fixed or seized tow pintle; remove the lock plate located under the lunette. The drawbar has two positions. The drawbar is lowered for travel, and raised for firing.

There are two lifting brackets to connect slings to, when the howitzer is being lifted by helicopter. A third bracket is located on front yoke. The carriage handles are used by crew members to lifting and shifting the howitzer during loading, unloading, and emplacing the howitzer.

The firing platform attaches to the howitzer lower carriage by using a socket and a locking handle. The eight holes are for the stakes needed to stake the howitzer in position. Platform stakes are issued in three sizes. There are four 15-inch stakes issued. These are used for frozen or rocky terrain, and are normally issued only where needed, such as extremely cold areas. There are eight 24-inch stakes issued, and they are used for hard packed ground. Four 38-inch stakes are issued to be used for soft ground.

The first production versions were displayed with a muzzle brake, most likely to allow long range 105mm rounds to be fired, but was discontinued before shipment to Vietnam.