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The W-76 Warhead

Intermediate Yield Strategic SLBM MIRV Warhead

Last updated 1 September 2001

The W-76 is the warhead used with the Mk 4 reentry vehicle which arms Trident I (C-4) and Trident II (D-5) submarine launched ballistic missiles (SLBMs). Designed for use on MIRV (multiple independently targeted reentry vehicle) bus upper stage.

W-76/Mk-4 Warhead/Reentry Vehicle Package
Yield100 Kilotons
Weight362.5 lb
Body Diameter?
Number In Service3000

Design Features

Two stage thermonuclear warhead

RV CEP (circle error probability) is 1250 feet


Probably contains beryllium reflected plutonium core
Deuterium-tritium boosted
Probable thermonuclear fuel is lithium-6 deuteride.

Delivery Method

Trident I C-4 (UGM-96A) or Trident II D-5 SLBM. Trident I can carry 8 W-76s (up to 14 with reduced range), the Trident II can also carry 14 (without reduced range). Based on Ohio-class ballistic missile submarines.

Safeguards and Arming Features


Fuzing and Delivery Mode



Designed and developed by Los Alamos National Laboratory (LANL).
Development cost for this warhead was $128 million.

Developmental problems were encountered, including an unexpectedly low test yield after a minor design change, and the discovery of nuclear effects vulnerability in the fuzing and firing system.

W-76 Development Schedule
May 1973 Development engineering begun at LANL
November 1975 Production engineering begun
June 1978 First production units completed
November 1978 Quantity production begun
July 1987 Production completed


Initial manufacture June 1978
Initial deployment 1978
About 3000 W-76 warheads have been manufactured.
Currently in service: 3000 warheads
Under START II 1280 W-76 warheads will be kept in service. The remainder will be retained permanently as part of the enduring stockpile either in the ready "hedge" stockpile, or in the reactivatable "inactive " stockpile.