M853-series cartridges are base-ejecting, illuminating cartridges. They have an aluminum body with an MTSQ
fuze, a fin assembly, and propelling charges. They are used in the M252 improved 81-millimeter mortar system.
Their color code is a white body with black markings. The DODIC for M853-series cartridges is C871.
120-Millimeter Mortars. These are heavy company-support weapons. They are used against personnel, to
provide illumination, and to provide screening smoke. These mortars replaced the 4.2-inch mortar system.
Examples of 120-millimeter mortar cartridges are shown in Figure 2-22.
The M57 is a 120-millimeter cartridge with an HE filler. It consists of a high-fragmentation steel body with a PD
(superquick or delay) fuze, a fin assembly, and propelling charges. The fuze functions upon impact. The color
code for the M57 cartridge is an olive-drab body with white markings. Its DODIC is C788.
The M91 is a base-ejecting, illuminating, 120-millimeter cartridge. It consists of a steel body with an MTSQ fuze,
a fin assembly, and propelling charges. Its color code is a white body with black markings. The DODIC for the
M91 cartridge is C790.
The M68 cartridge contains a bursting WP smoke filler. It consists of a steel body with a PD (superquick or delay)
fuze, a fin assembly, and propelling charges. The fuze functions upon impact. The color code for the M68
cartridge is a light-green body with black markings. Its DODIC is C789.
Mortar Fuzes. Some mortar cartridges are issued as complete rounds (including fuzing), and some are
issued without fuzes. For fuze-cartridge combinations, refer to TM 43-0001-28, Appendix A.
Fuzes are classified according to how they function (such as PD, mechanical-time [MT], MTSQ, proximity [PRX],
and multi-option). The paragraphs that follow describe some of the fuzes that may be encountered with mortars.
Examples of PD fuzes are shown in Figure 2-23. The M524-series PD fuze is used with HE and WP 81-millimeter
mortar cartridges. This fuze is designed to provide dual-purpose (DP) functioning (upon impact or upon grazing)
with a superquick action.
The M525-series PD fuze is used with 60-millimeter and 81-millimeter HE, practice, and WP cartridges. This fuze
is designed to function upon impact or superquick.
The M745 PD fuze is used with the 60-millimeter WP smoke cartridge (M722). This fuze functions upon impact
Examples of time fuzes are shown in Figure 2-24. The M768 MT fuze provides a variable-time capability for use
on the illuminating and smoke cartridges for the M252 improved 81-millimeter mortar. The time on the fuze is
preset by the loading crew.
The M776 MTSQ fuze is designed for use with the M721 60-millimeter illuminating cartridge. The time on the
fuze is preset by the loading crew. This fuze includes an impact back-up that functions if the time device fails or
the time setting exceeds the time of flight.
Examples of proximity fuzes are shown in Figure 2-25. The M517 proximity fuze is designed for use with M362-
series 81-millimeter HE mortar cartridges (when used against surface targets). This fuze is armed during flight,
and uses an impact back-up system.
The M532 proximity fuze is designed for use with 81-millimeter HE and WP mortar cartridges. This is a dual-
purpose (proximity or PD) fuze. The setting is selected by the loading crew, and cannot be reset once selected.