Fuze-Setter - M1

This is a rare example of a Mechanical Fuze-Setter, has seen active service still in good condition. Typically used on M501 and M520 USA fuzes, from the 1950s through to the early 2000s.

M501 Series:

January 1955 alongside the M26 fuze setter. It was designed as a dual-purpose (timed or impact/superquick) clockwork fuze for spin-stabilized projectiles

Primary Active Era (1950s–1970s): The fuze was heavily utilized during the Vietnam War, commonly paired with 105mm and 155mm howitzer illumination rounds (like the M314 series) and 4.2-inch mortar systems.

Phased Replacement (Mid-1960s onward): The M501 series began being phased out by the newer M564 and M577 MTSQ fuzes. The M564 provided a safer delay arming mechanism and extended the max timing capability from the M501's 75 seconds up to 100 seconds for longer-range artillery.

Obsolescence (Late 1990s/2000s): While heavily replaced in frontline stockpiles by the 1980s, the M501 series remained documented in official U.S. Army ammunition data sheets (such as TM 43-0001-28) well into the 1990s and early 2000s for legacy ammunition reserves and training purposes.

The M520 Mechanical Time and Super-quick (MTSQ) fuze:

 This series saw its primary operational use spanning from the late 1950s through the late 1970s and 1980s, with a heavy concentration of service during the Vietnam War (1962–1975). 

Operational Timeline & Status

Introduction (Late 1950s): Developed and introduced by the United States as a primary dual-purpose (airburst time delay or super-quick impact detonation) artillery fuze for rotated ammunition.

Peak Service (1960s – 1970s): It served as a standard issue item during the Vietnam War across various field units. For instance, Australian and U.S. 105mm and 155mm howitzer units relied heavily on the M520 during this era. 

Phased Phased-Out / Replacement (Late 1970s – 1980s): The U.S. Army began phasing out the M520 as standard-size body fuzes like the M564 and the M577 series were fielded to replace it. 

Current Status: The M520 is Obsolete / Out of Active Service in modern Western militaries, though stockpile examples or foreign derivatives (such as the Italian M520C4 copy) can still occasionally be found in older global ordnance inventories.

Condition is used, but not too heavily.

The handle is for a battery to illuminate the setter at night, which is not present.

The weight is 2.660Kg - hence the high cost of postage; even by courier.