C27

Caliber: 5.7x28mm
Length: 16 inches / 406 mm
Barrel Length: 8 inches / 203mm
Weight: 4.5 lbs /2 kg
Rifling: 5 grooves, right hand twist
Capacity: 40 round box magazine
Muzzle Velocity: 2,345 fps / 715 m/sec
Accuracy: ~ 4 MOA
Effective Range: 65 yards /60 meters
Maximum Range: 142 yards / 130 meters
Action: Open bolt blowback. Full automatic only, 700 rounds per minute.

A fairly simplistic looking weapon, little more than a steel pipe with a trigger and a magazine sticking out of it, the C27 is, like a number of World War II era submachineguns, much more than a simple piece of forged metal. Like its World War II forebears, the C27 is an inornate, fairly basic weapon, however its concept is a new one, that of an under-barrel submachinegun. Like the M203 grenade launcher and the M26 shotgun, the C27 was purpose made to be installed beneath the barrel of a combat shotgun or an assault rifle so as to increase the gunner's rapid fire capability as well as add another degree of combat capability.

Primarily, the C27 was designed and intended for use with military shotguns, weapons that tend not to have a high rate of fire nor a large ammunition capacity. Due to these two circumstances, shotgunners can find themselves in a tight situation during heavy combat, especially in the realm of close quarters combat. Though shotguns allow for devastating short range power, even fully automatic ones tend to have slow rates of fire compared to other weapons, while the size of their ammunition tends to limit their magazine capacities to usually less than a dozen rounds.

The C27 addresses this problem by providing an instantly available, high capacity, rapid fire weapon to the shotgunner. With its pistol grip acting as a forward grip for the gunner, his hand is already in position and ready to fire and when needed for combat he need to only disengage its safety and pull the trigger. The ambidextrous safety is immediately above the gunner's thumb and is easily engaged and disengaged within one second, and without needing the gunner to take his finger off the trigger.

For the basic firing mechanism, the C27 is built on the durable and mechanically simple PPS-43 platform. Field stripping into only two parts, the C27 is a simple weapon to manufacture and an immensely easy weapon to maintain, thus allowing the gunner to keep a secondary weapon on hand and ready to go while adding only about 5 more minutes of cleaning and maintenance time to his workload.

In addition to mechanical simplicity, the PPS-43 platform was chosen due to its small size and compact frame, both of which are critical when being installed as an adjunct platform to another weapon system. To further reduce encumbrance, the C27 is machined from titanium alloy, making it much lighter than traditional steel while maintaining its strength. For further durability and greater longevity, the barrel is chrome lined.

In order to minimize the overall size of the C27, it borrows the magazine and ammunition loading concept of the P90 submachinegun. The bullets lay flat in the magazine, side by side from front to back. The magazine itself is installed on the bottom of the C27 and lays flat against its receiver. When a round is to be chambered, it rises along a fixed, helical ramp that rotates it 90 degrees to be aligned with the barrel. Also borrowed from the P90 is the 5.7x28mm ammunition as its small size helps keep the C27 as compact as possible while allowing for a sufficiently large ammunition capacity.

For installation, the C27 mounts to the host weapon much the same way as the M203 grenade launcher. Due to the progressively increasing use of Mil-Std M1913 accessory rails, C27s can also be had with mounts that allow it to be installed on M1913 rails as well, thus allowing weapons both with and without rails to accommodate the submachinegun. Although intended primarily to be installed on military shotguns, the C27 can be mounted on a wide range of weapons. When installed on assault rifles such as the AK47 and the M16, the parent rifle can be used for longer range work, while the C27 can be reserved for close quarters engagements. A further advantage of the C27 is that because the 5.7mm rounds were purposed designed to minimise over-penetration, it can be employed in situations where the parent weapon's rounds would over-penetrate and cause unwanted collateral damage and even possible casualties.

If needed or desired, the C27 can be employed as a stand-alone weapon by itself. A specially designed stock is fitted to the rear of the receiver and locks in place using the C27's shotgun/rifle installation mounts. A set of sights, similar to those of the PPS-43 are installed on top of the stock, although instead of being calibrated for only two distances, the C27's are calibrated for 3 distances; 50, 100 and 200 meters.