These bombs are all general purpose high explosive bombs.
The 1000 lb GP Bomb AN-M65A1 has a cylindrical metal casing, an ogival nose, and a tapered aft end. A box-type fin assembly is secured to the aft end of the bomb with a fin locknut.
Both a nose and a tail fuze are generally used for the majority of operations with this bomb. The AN-M65A1 uses an adapter-booster that will accommodate tail fuzes with 2-inch diameter threads. A fuze adapter is used on the inside of the adapter- booster to convert the seat to accommodate fuzes with the smaller 1-1/2 inch threads.
Special studs attached to the base plug and imbedded in the solidified explosive filler prevent removal of the base plug. The adapter-booster and fuze adapter are locked to the base plug with a locking pin that extends from the adapter-booster to a groove in the base plug.
Approximately 50 percent of the complete weight of the bomb is explosive filler. Double suspension lugs are welded 14 inches apart and a single suspension lug is welded to the opposite side of the bomb case.
The bomb is painted olive drab; yellow color bands and black stenciled nomenclature identify the bomb and its high explosive charge.
The AN-M65A1 bomb contains antiwithdrawal pins in the base plug and an adapter-booster and fuze adapter that can be locked in place. The earlier AN-M65 bomb lacks these antiwithdrawal features.
Released weight of the AN-M65 is greater than that of the AN-M65A1, the AN-M65 having an explosive charge of 53 percent as compared to the 50 percent ratio of the AN- M65A1 bomb.
The AN-M44 bomb, an earlier model of the 1000 lb GP bomb, is similar to the AN-M65 but has an Adapter-Booster M102 assembled which will accept only fuzes with a 1-1/2 inch diameter thread. US Bomb, 1000 lb GP, AN-M44, AN-M65, AN-M65A1 (bulletpicker.com)