MODEL 601 | AUTOMATIC GUN-MORTAR
Developed as a private venture by the state run arsenal and design bureau in Deckai (DDB), the 601 was developed in under nine months and was given its official designation upon adoption by the Amastoli Armed Royal Forces less than a year after development began. Designed specifically for light armoured vehicles - being the Javelin Mortar Carrier Vehicle in New Hayesalian service - the 601 gives light armored vehicles a very strong weapon for both infantry support and for direct engagements of enemy armored vehicles including APCs and other front line light armored vehicles.
The quick concept and development was thanks primarily to rapid prototyping, but also due to its simple and rugged design, the reliability of such which is a boon to vehicle commanders. It was not till its adoption that the weapons true potential as a support weapon became fully realised, its use in MOUT and the close confines of the Amastolian forests made it a favorite of platoon leaders who could frequently call on it for assaulting enemy positions or providing a very effective 'door knocker' in urban engagements.
The model 601 Automatic Gun-Mortar is a short recoil operated weapon firing from a fixed rotary magazine. Upon ignition and firing of the round, the barrel and bolt recoil together locked via the barrel extension for approximately one-hundred and twenty millimeters upon which the bolt engages a cam on the top of the receiver, rotating the bolts faces four lugs out of alignment unlocking the bolt from the barrel extension. The Barrel returns to battery under the pressure of its own hydropneumatic recoil spring, allowing the lighter bolt to continue rearwards within the receiver allowing for the next round I n the magazine to rise up, before the pressure of the internal spring forces the bolt forward again stripping round from the magazine and locking the breach by means of the barrel extension. The 601 fires from a closed bolt allowing for improved direct fire accuracy, and indirect fire range and decreased preparation times for firing. Due to the delayed opening of the bolt however very few fumes are able to enter the cabin, however a small supplementary non-concentric fume extractor is also fitted so as to improve operator comfort and weapon reliability.
The weapons high rate of fire is designed to allow for high impulse burst of fire, placing three rounds downrange in two point one (2.1) seconds, and though capable of sustained automatic fire this feature has been factory disabled in order to extend the service life of the weapon and decrease its mounting strain.
Burst length is controlled by the fire control system which also controls the fuse setting allowing for a mixture of burst heights and fuse setting in order to better suppress the enemy within the target area. A three round burst contains the equivalent weight of munitions compared to an eighty-one millimeter (81mm) mortar round yet is able to fill the equivalent area of effect of a one-hundred and twenty millimeter round (120mm) at one third the weight, and almost half the cost.
The fixed rotary magazine is based loosely on an improved Johnson style rotary magazine. The 601 is capable of being loaded with individual rounds or by means of a powered loader, which can feed from a larger internal secondary magazine. With the many variations on 60mm round length a special spring loaded adjuster plate as been integrated into the magazine design which allows the rounds to remain loose horizontally in the magazine until the last centimeters of magazine space in which ace the rounds are gently slid forward against the front wall of the magazine where tension with other rounds holds them in place. Should a shorter round be followed by a longer round, the pusher plate (which is a spring loaded angled plate) will conform to the longer rounds length (by means of adjusting to a shallower angle) and align it properly with the front wall of the magazine a before pressing back to its original angle. This system will support assorted rounds ranging from two hundred and seventy-five to four hundred and thirty millimeters in length. It should be noted this arrangement is made possible only due to the gun-mortars unusual continuous bore breech, not being restricted by head spacing of a rounds cartridge as most guns are.
Due to the magazines design, individual speciality rounds may be added at the top of the magazine to allow for a magazine of offensive rounds to be kept at ready while specialty rounds (such as illumination or anti-tank rounds) are loaded and fired one at a time. Fuse programming is automatic (with compatible M630 Advanced Multi-Option Fuses) and is set from the ready position of the magazine before chambering. The method used is induction by means of a specially coated touch plate at the front of the magazine wall which allows rounds fitted in the magazine to slip past this plate as its raises upwards in the magazine. This allows for rounds to be superseded by specialty rounds as needed, yet remain programmed (or indeed be reprogrammed) upon the firing of those rounds. A secondary safety is in place that is deactivated by the round being inserted into the weapons breech decreasing the chance of premature or internal detonation.
Recoil attenuation is achieved by means of a pair of forty-millimeter hydropnuematic accumulators, and a ported radial muzzle brake containing forty-two five-millimeter cutouts. The combination of muzzle brake and accumulators decrease the weapons recoil to make it more suitable for employment on light vehicles. Ignition of the rounds is electrical allowing for shorter lock times and the ability to safely restrike the primer with the system with out opening the breach. The major disadvantage however is the loss of the ability to use rounds dropped fired into the muzzle, however due to the intended deployment and muzzle brake (and its blast effects on close personnel) it was deemed as less advantageous compared to the safer electrical igniter.
The cold forged monoblock smoothbore barrel and major internal components are hard chromed and molybdenum-disulphide coated for decreased wear and improved service life. The outside is Titanium-Nitride (TiNi) coated for superior corrosion resistance, and then painted with a rust preventive primer prior to shipping. This combination of coatings and surface treatments improves the weapons service life in inclement conditions including saltwater, cold weather, etcetera. This multiple layer protection scheme serves the weapon well while working away from central repair centers and in the mud with the infantry as a light weight but lethal support weapon.
Though the 601 is capable of firing a large majority of the worlds sixty-millimeter mortar munitions DDB designed in parallel with the 601 a new series of 60mm projectiles in order to obtain the best possible results from their new weapon. Original developments were built upon the rounds originally developed for the Denel LR M6 mortar system; however certain design changes were enacted in order to better function with the weapon itself.
This new family of rounds is designed to use the newly develop M604 induction programmable multi-option fuse. The three-option fuse allows for Air-bursting (from 1 to 5 meters off the ground, or timed), Impact, and Delayed impact modes to be selected and programmed by the system fire control prior to firing. Redundant systems allow for failure of one fuse setting to default to the following setting so as to ensure on target effect.
Types of rounds available include high explosive, smart light anti tank, thermobaric, smoke, illumination (IR and visible), and training.