ОФС на Абрамсе

Use:
This cartridge is a high explosive, obstacle reduction,
tactical service round with tracer. The M908 is
used in the 120mm, smooth bore M256 cannon.
Description:
The Cartridge; 120mm, HE-OR-T, M908 is a
high explosive, obstacle reduction, tactical service
round with tracer. The M908 is used in the 120mm,
M256 smooth bore tank and is a fin stabilized round
with a discarding sabot. The baseline design contains
a propulsion system consisting of a combustible cartridge
case, case adaptor, nineteen-perforated hexagonal
JA-2 propellant, a propellant containment device
(cloth bag), and an M129 primer assembled to a
metal case base and seal assembly (all are currently
used on the M829A1). The projectile consists of a
subcaliber projectile and three piece aluminum sabot.
The subcaliber projectile combines a fuzing system
and a chemical energy warhead (Composition A3
Type II). The three segment sabot is secured to the
warhead body by a nylon obturator and a steel retaining
ring. The fuzing system includes: M774 base
element, flexible communication circuit, and frontal
impact switch assembly (FISA). The conical nose of
the projectile consists of the FISA coupled to the warhead
body and a steel nose coupled to the FISA,
which closes upon impact with a ground target. A
flexible electrical cable carries the signal of FISA
closure to the M774 base element. An inertial switch
in the M774 base element act as a backup to the
FISA. Either switch will delay the function of the
warhead beyond the point of impact with the target.
This delayed functioning is ideal for the reduction of
concrete ground targets.
The M774 base element is a dual environment
safe and arm (S&A) device. The M774 receives an
electric firing pulse from the FISA which then triggers
the base element electronics to fire the M69 electric
detonator. The M69 detonator is contained in the
rotor which provides a physical separation of the
M69 detonator from the fuze electronics until the
subprojectile has traveled a safe distance downrange.
The first safety feature of the mechanical.
S&A lock consists of three leafs and a spring,
originated so as to release the rotor upon forward
acceleration. The second safety feature is a drag
weight which senses the decelerating force/drag of
the projectile as it leaves the muzzle. As the drag
weight senses drag, it moves out of the way of the
rotor allowing the rotor to rotate to the armed position
as designed.
Once the M774 base element is armed and
receives an electrical firing pulse to trigger the detonator,
the detonator, lead, booster, and warhead
explosives initiate in sequence destroying the target.
The explosive train located in front of the base element
consists of the lead cup, booster, and Comp A3
explosive. The warhead explosive is contained in the
body with a shaped copper liner, in front of the
booster. The liner provides the penetration capability
for the system.
An aluminum fin assembly with tracer is
attached to the aft end of the subprojectile by way of
an aluminum fin adaptor. The fin has beveled leading
edges and T-tabs on the outside diameter to increase
the effective fin area. Spin, which is inducted by a
twist in the fin blade, provides the subcaliber projectile
with greater in-flight stability and accuracy.