The creation of the Army-Navy Standardization Commitee resulted in the standardiza-tion of the bomb of these two services into the AN series. This series was very similar to the "M" series except for these modifications:

A third suspension lug was added at the center of gravity and diametrically opposi-te the dual suspension lugs to fit British release devices.

The base plate was changed to a male plug to increase the strength on low angle penetration of targets.

(c)

The bombs were painted an overall olive-drab with 1" yellow bands around the nose and base and a 1/4 inch yellow band around the center of gravity.

The bombs in this series included the followings weights: 100#, 250#, 500#, 1000#, and 2000#. These bombs are all general purpose high-explosive bombs. Though other types of bombs (i.e. armor-piercing, semi-armor piercing, fragmentation, incendiary, depth, etc.) have been subsequently standardized and given AN designation, it is with the AN general purpose bombs and their modifications that this introduction shall be con-cerned.

AN G.P. Series:

The AN series was subsequently replaced by the AN G.P. series to make it possible for these bombs to be used in anti-submarine work as well as for general bombardement. This modification was incorporated into the 500#, 1000#, and 2000# bombs only, their new designation becoming AN-M 64, AN-M65, and AN-M66, and consisted of a change from the M120 adapter booster, to the M115 adapter booster. With the M115 adapter booster, it became possible to use wither standard Army tail fuzes or the AN-Mk 230 tail hydrostatic fuze. The standard filling of these bombs was 50/50 Amatol until the supply of T.N.T. became ample in 1943 at which time T.N.T became the standard filler. At the present time, 25% of the production of these bombs is filled with Composition "B".

AN G.P. A1 Series:

The A1 modification consists of two steel pins in the base plate which looke the base plate to the main filling, thus preventing removal of the base plate once the bomb is fill-ed. In this series the adapter booster have also been modified to the M102A1 and M115A1. This modification consists of a hole through the adapter booster and a groove in the threads of the base plate to receive a locking pin which is shipped with an anti-withdrawal tail fuze. Insertion of the pin which is held in by the fuze body prevents with-drawal of the adapter booster. This series is the current production G.P. bomb series and is used jointly by the Army, Navy, and British.

General Purpose Bomb Designation:

The following table will assist in understanding the development of the designations that have been successively applied to general purpose bombs used by the Army and Navy: