Weapon Name- M328
Round Type- 28mm Grenade
Over-all length- 27.5 (698.5mm), 21 inches (533.4mm)
Barrel length- 24 inches (609.6mm), 17.5 inches (431.8mm)
Weight-3 lb, 3.375 (loaded)
Rate of Fire- 210 RPM
Feed Mechanism- Internally tube fed
Round Capacity- 3
Effective Range- 500 Meters
Range- 1000 Meters
Accuracy- 3 MOA
Accessories- Laser Ranger Finder, Round Counter
Quick switch firing mechanism- Extra Trigger
Scope/Sights- Thermal Scope
Muzzle Velocity- 215-420 m/s 52 grams
Firing System- Internal Metal Storm Tube
Miscellaneous/electronic information- Essentially a semiautomatic 3GL 3-round 25mm grenade launcher attached on top of the weapon, rather than underneath like most underbarrel grenade launchers.
Basic Information
The weapon is essentially a semiautomatic 3GL 3-round 25mm grenade launcher attached on top of the weapon, rather than underneath like most underbarrel grenade launchers. The grenade launcher inherently designed to be integrated with an assault rifles, specifically the M7 and M12 AMAWS, although it can be attached to any weapon with a top picatinny rail. The weapon is an open breach, single tube grenade launcher, similar to the 3GL, which can simultaneously fire multiple air bursting grenade launchers on an assault rifle, without possessing excessive size or weight. The overall concept was to make a primary combat rifle which could also utilize air bursting 25mm grenades, in a manner similar to the XM29 or PAPOP designs. To increase soldier effectiveness, and serve as a force multiplier, grenade launchers that can fire multiple rounds, especially if paired with an existing assault rifle (to allow virtually any soldier in the squad to maintain a degree of self defense or practicality when fullfilling the grenadier role), were largely seen as the next step in small arms, particularly when utilizing programmable smart grenades, that could explode in mid air, allowing for the acquisition of defilade or hidden targets. While these weapons were considered too bulky or heavy to be useful to the average soldier, this particular design seeks to overcome those issues by using a much compact design, that doesn't rely upon reciprocating bolts or large magazines, but rather a single tube firing similarly to a Roman candle, that is essentially the same length as the overall rifle, rather than an underbarrel grenade launcher, which is much shorter, or an underbarrel rifle, which is also much shorter. In this manner, both weapons retain their general effectiveness, without being extremely heavy. The grenade launcher portion (High explosive, or HE) of the weapon can hold up to 5 rounds, although usually it only holds 3.
To account for the reduced complexity and bulk in the design, and the inherent difficulty of utilizing such a weapon, the weapon uses caseless rounds, which also have the added benefit of being lighter weight than normal cartridges, and are ignited by electricity. Ordinarily, there would be many factors one would need to account for that would make a stacked, superposed gun difficult to use, or impossible, or essentially design challenges for such a weapon. First, there would need to be a way of removing the empty shell once the round had fired; for bullets to fire one after another, without the weapon ejecting the shell like in a typically reciprocating bolt, one would need to find a way to remove the sell, or like the current design, not have a shell, or case at all. Second, in order to allow for the complex manner of fire, no firing pin or bolt assembly could be present, which necessitates a form of fire which can fire off any round in the weapon regardless of it's placement. Finally, the increased stress and heat inside the weapon would need to be eliminated or accounted for, with more heat resistant bullets. The weapon accomplishes all of this by using electrically ignited caseless rounds. Caseless rounds have no worry of shells being ejected, since they possess no cases, and thus can fire one after another without running into the discarded remains of the previous rounds. The weapon uses a heat insensitive binder, which increases the temperature of which cook offs occur, which means the splash back effect of the previous cartridge has less effect than with traditional bullets. It also uses an electrically ignited primer and propellant, which inherently don't rely on kinetic energy to detonate them, thus removing the fatal flaw of KE prone propellants being accidentally set off due to poor maintenance or the increases stress of firing multiple cartridges in a weapon at a time. Finally, the weapon owes the simplicity and small nature of it's design to the fact that the electrically ignited primers merely touch a small band of metal to be ignited, rather than a complicated firing pin system, which allows them to be fire successively without them getting in each other's way. In this way, the weapon can effectively achieve a stacked roman candle like design of firing it's rounds, using a single tube as the barrel, to fire the rounds, and to hold on to the rounds, acting like a magazine. The weapon is breach loaded, and individual rounds, or stacks of rounds, can be loaded into the weapon.
Due to it's simplicity and lack of moving parts, other than the trigger and bullet, this grenade launcher is only approximately 2.25 pounds. Because it spans the entire length of the rifle, it also has an incredibly long barrel length; as each round fires, it increases the overall length of the barrel, or the length of rifling imparted on each cartridge, since each round takes up space inside the barrel. However, these differences are relatively marginal, and in any case, compensated for inside the rifle by changing the amount of propellant burned, meaning the last cartridge has a small amount of propellant wasted inbetween each round fired, to give the identical ballistic properties. Each round is approximately 56 grams total, and thus 3 rounds adds approximately .375 pounds of weight to the weapon system. However, an enhanced cartridge is 68 grams and it allows for double the range, despite using the same cartridge. The inherent flexibility of the system allows for a wider variety of cartridges to be able to fired, and allows for more rounds to be fired more quickly. The caseless nature of the rounds not only make them more practical, but lighter weight, which allows the soldiers to carry more. Unlike traditional grenade launchers, the grenade launcher utilized is placed on top of the weapon, which increases the virtual barrel length and allows more rounds to be loaded in to it. It utilizes a substantially smaller, airbursting 25mm grenade, which makes it just as capable as a 40mm grenade, but lighter weight, allowing more rounds to be carried. The round is detonated using a laser range finder and a thermal scope.
