Original Item: Only One Available. This was intended for practice and training and was not filled with any explosive content. The propulsion charges are inert and or not present, making this round BATF compliant. This cannot be converted back to a “live” destructive device and is Not Available For Export.

U.S. Army Yuma Proving Ground and other training location’s primary mission is to test equipment to ensure it works anywhere in the world. This includes virtually everything in the ground combat arsenal, including items that are meant for training men and women in uniform for combat.

The M769 Full Range Practice Round, which has the shape and characteristics of the 60 mm mortar round commonly used by combat infantrymen, is one such item. Though not used in combat, the Army and Marine Corps fully rely on the M769 to function safely and effectively in training situations.

The complete round consists of a hollow projectile body with vent tube, a PD practice fuze, a fin assembly, four increments of propellant charge, an ignition cartridge and obturating ring. The cartridge is similar in appearance to M720 and M720A1 HE cartridges.

When the cartridge is loaded, it slides down the mortar tube. The firing pin at the bottom of the tube initiates the primer. The flash from the primer ignites the ignition cartridge, which in turn ignites the propellant charge. Rapidly expanding gasses from the burning propellant expand the obturating ring, accelerating the cartridge and propelling it in flight.

Stabilization in flight is accomplished by aerodynamic and spin action of the fin assembly. The fuze functions upon impact with the ground or target. A pyrotechnic smoke cartridge in the fuze produces a flash, audible sound and cloud of smoke, to simulate the HE function. Upon functioning, the plugs are expelled from the holes in the base of the projectile, allowing the smoke cloud to vent through the holes.
The Components Featured On This Round:

Consists of: M781 Fuze, Body, Obturating Ring, Tube, Vent Holes, M27 Fins (undamaged), M702 Ignition Cartridge.

- FUZE, PD PRACTICE M781: The M781 is a single safe point detonating fuze for use on the M769 60mm Full Range Practice Round. It simulates the appearance of the M734A1 Multi-Option Proximity Fuze (same settings but they are not functional). Smoke and flash are emitted through holes in the rear of the mortar cartridge. When live, it has a pyrotechnic smoke composition charge of 12 grams.

- Obturating Ring: Although not present, it is important to know why there is a groove around the midsection of the body. An obturating ring is a ring of relatively soft material designed to obturate under pressure to form a seal. Obturating rings are often found in artillery and other ballistics applications, and similar devices are also used in other applications such as plumbing, like the olive in a compression fitting. The term "O-ring" is sometimes used to describe this kind of pressure seal. Obturating rings are common in artillery, where the hard steel casing of the shell is too hard to practically deform to provide a tight seal for the propellant gasses. An obturating ring or driving band made of a softer material is the typical solution. Mortar bombs also use obturating rings to provide a seal around the projectile. Recoilless rifles and some artillery use rings with a reverse impression of the rifling cut in them for a tighter seal even at very low pressures.

Some artillery shells use an obturating ring at the rear of the shell to provide a tight seal for the breech. This allows a mostly caseless ammunition without the sealing issues generally encountered in such ammunition. The obturating ring provides the sealing that would normally be provided by a cartridge case.

- M27 Fin Assembly: The M27 Mortar Fin supports the 60mm family of mortar items. It is a single piece design approximately 5.4 inches long and 2.4 inches in diameter at the blades, machined from an extrusion of 6070-T6 or 2014-T6511 aluminum. Each fin blade is precisely canted at 5 degrees and the center of the fin is hollow to allow insertion of an ignition cartridge. Gas and flame are vented from the ignition cartridge through flash holes drilled in the boom section of the fin.

- M702 Ignition Cartridge: The 60mm (M702) Ignition Cartridge and the 81mm (M299, M752A1) Ignition Cartridges are comprised of an aluminum head/body assembly that holds a capped paper tube filled with a prescribed amount of propellant. The head/body assembly contains a firing plug that, when dropped down the mortar tube, locally compresses a percussion primer that initiates the energetic train. The primer's output initiates a black powder pellet. The output from the black powder pellet travels through a flash tube to initiate M9 propellant inside the paper tube assembly. The Ignition Cartridge is loaded with a prescribed amount of propellant capable of providing a muzzle velocity necessary to achieve required 60mm and 81mm High Explosive (HE), Smoke, Illumination, and Full Range Practice Cartridge (FRPC), mortar cartridge ranges.

This is a wonderful example of a full range practice round that shows signs of being used but does not appear to be damaged and retains almost all of the original paint and markings.

Comes more than ready for display!