"The first MK6 Mod6 entered
the national stockpile in January 1955.
By November 1956, all MK6 weapons had been converted to Mod6
configuration by installation of the new baro and contact fuses. The last MK6 Mod6 was retired in 1962.
Late mods of the MK6 (as well as late mods of the MK 7) used new MC-193
nickel-cadmium (NiCad) storage batteries that replaced the ER 12-10
The MC-193 required a charging time of only one hour, after
which it held a full charge anywhere from one to 240 days, depending on
ambient temperature. The MC-193 was produced by the Sonotone Corporation
starting in May 1952; production was complete by December 1953, at which
time almost all ER 12-10 batteries had been withdrawn from stockpile.
Approximately 1,100 MK6s (in all mods) were produced
between July 1951 and early 1955; it was the first U.S. nuclear weapon
to be produced in large quantity (over 1,000 units). The MK6 stockpile
was augmented by a number of MK18s converted to MK6 Mod6s between
January and March 1956.
Among USAF jet bombers, the B-47 could carry one MK6, while the
B-52 could carry two, although the carriage of atomic bombs by both
aircraft was soon superseded by carriage of higher-yield thermonuclear
bombs. The MK6 used a 120 lb. natural uranium tamper." *
* Swords of Armageddon, Volume VI, Hansen.