The Personal Defense Weapon, Caliber .30, Carbine, is a compact, magazine-fed, open bolt, electronic impulse, electromagnet-assisted delayed blowback-operated select-fire assault rifle employing the new 7.62x33mm Caseless round, intended to supplement the hand phaser as a backup weapon carried by non-combat support personnel for personal defense in active warzones. Additionally, with the use of specially-coated subsonic ammunition and a sound suppressor, it can be used in clandestine special operations missions to spoof station sensors and avoid setting off automated alarm systems.
History
The PDW-30/C has it's roots in the TR-240 project, as during Solas Tempus R&D's pursuit of a lighter weight weapon system, they developed a new, caseless telescoped round. With the acquisition of advanced ballistic propellant from the 4th millennium, Solas Tempus R&D was able to compact the then-standard ballistic round, 7.62x51mm M118 AP-FMJ (famously used by Spartan supersoldiers in the MA5-series of battle rifles), into a smaller casing, using technology, techniques, and designs from just before projectile weapons were widely considered to be obsoleted by more powerful directed energy weapons. The result was a caseless round: 7.62mm in diameter and 33mm in length overall.
Before the adoption of 7.62x33mm Caseless was even considered, designers began to develop a new PDW, cutting costs by adapting a previous, older design, the ubiquitous AR-15 platform of the mid-20th and 21st centuries, and placing a distinctive twist on it. The result was the PDW-30/C, accompanying the release of the new round, which is designed to be an easy-to-operate backup weapon for non-combat or foreign personnel to instill more confidence in their presence in contested areas, with a distinctly more aggressive look than a hand phaser or Type 3 phaser rifle. However, it cannot match the utility or overall power of a phaser, and is only designed as a supplemental weapon, rather than a replacement.
Additionally, Temporal Operatives and other branches of Solas Tempus TACCOM have taken an interest in the weapon for an offensive role, as specially-coated bullets and sound suppressors can be combined to create an effective weapon that retains killing power without setting off alarms, especially for operations where stealth is paramount. In particular, the caliber of projectile (.30 calibers, or 7.62mm) and overall appearance of the weapon, which bears resemblance to custom AR-15 variants found in civilian hands, make it an appealing choice for missions taking place in the 20-22nd centuries, as the design wouldn't arouse suspicion and violate Temporal Regulations while retaining enough power to deal with most threats to Temporal Operatives while in the field. Specially-modified PDW-30s for TempOps are designated as XPDW-30/TO
Design
The PDW-30/C operates on an electronic impulse, delayed-blowback open bolt action, feeding from specialized 50-round stick magazines that store rounds perpendicular to the bore axis, similar in design to the P90's stick magazine. Essentially, the feed lips of the magazine are attached to a gate that rotates 90-degrees, placing the next round along the bore axis and allowing the bolt to carry the round into battery. The advanced primer ignition system uses an electronic impulse to fire the primer very briefly before the bolt actually goes into battery, which normally requires precise timing based on different ammunition types to maximize efficiency. However, a lithium-ion battery located inside the "magazine well" powers an electromagnet as well as the firing pin, which compensates for different recoil forces and ensures perfect operation of the mechanism every time. Due to the nature of the system, the rate of fire can be tuned via a recessed dial underneath the battery, from roughly 450 RPM up to 1,700 RPM.
The system itself reduces recoil forces compared to a regular straight blowback system, and special compensators and buffers in the stock serve to reduce the recoil even further to manageable levels. Surprisingly, the weapon only has two fire modes: safe, and full-auto. There is no semi-automatic function, although this is compensated by the tuneable rate of fire and the fact that the weapon is not capable of bump-firing or other accidental discharges common to open bolt designs due to the requirement of a full electronic impulse input from the battery and firing mechanism.
For amenities, the PDW-30/C features an ambidextrous fire selector, ammunition counter, 6-position buttstock, fully-customizable handguard with 4 modular rail units, and a rearwards receiver-mounted modular rail. Due to the nature of the magazine, which necessitates a cutout on the upper receiver, the rear rail area is relatively small, especially for mounting longer-ranged optics. As such, a modified Type 3 phaser rifle sight is most commonly used, or any variety of 21st century-era close-range optics in tandem with flip-up polymer sights. The design is fully modular, and can accept a variety of sights, stocks, grips, and other accessories, as well as longer or shorter barrels.
In the event that the weapon overheats, the bolt will automatically lock rearwards and the emergency ejection port will open. The weapon has an integrated temperature sensor that feeds information to most forms of ST-standard HUDs, but also seizes the operating mechanism up in the event that an ammunition cook-off is imminent. The ejection port can be manually operated and unlocked by means of the right-side-mounted charging handle, which is used to chamber a round but is otherwise non-reciprocating. When closed, the weapon's internals are fully sealed. A bolt-release paddle on the left side allows the operator to close the bolt and safe the weapon.
The PDW-30/C is entirely made from special stamped temperature-resistant alloys, with most parts made from high-grade polymers and tritanium alloys for durability and longevity. The result of this is a rather lightweight platform, at roughly 3 kilograms fully loaded with a 50-round magazine, but also one that is intensely durable and can withstand all types of environments and pressures.
Effectiveness
While the TR-240's version of the 7.62x33mm round was handicapped by the weaker design of the machine gun's receiver, which could not handle higher chamber pressures than those generated by the M118 round, the PDW-30 carries no such disadvantage. Thus, ammunition designed for the PDW-30 are significantly "hotter", or have significantly more power behind them. A standard 7.62x33mm Caseless Armor-Piercing, High Explosive, Incendiary round fired from a 10.3-inch barrel has a muzzle velocity of over 900 m/s, and carries more penetrative power at 100 meters than a regular M2 ball .50 BMG round. To avoid confusion, rounds designed for the PDW-30 are marked with a yellow ring around the lower end of the cartridge, while TR-240-compatible rounds are otherwise fully functional when fired from the PDW-30.
The free-floating barrel, as well as a minimal amount of moving parts and exceptionally tight tolerances, lends this weapon exceptional accuracy of roughly 0.5 MOA with an effective range of 700 meters with a 10.3-inch barrel and standard AP-I/HE ammo.
A special operations round is also being devised for the weapon, which is a smaller, explosive-tipped round with a special depleted uranium/tritanium-alloy penetrator, coated in a signature-reducing layer to avoid detection by the most common station sensors. Using an integrally-suppressed, ported 10.3-inch barrel, the system is able to spoof most sensors, while the heavier subsonic round is still capable of remaining lethal out to normal engagement ranges. It operates on a similar principle to the AP-I/HE round, although with a more subdued explosive effect designed to explode inside of a target and cause the most internal rupturing and damage possible.
Ammunition
There are several main types of ammunition designed specifically for the PDW-30, not including TR-240 rounds that are compatible with the PDW-30 platform.
Mark 30 Mod. 0 Armor-Piercing, Incendiary, High-Explosive
The standard-issue 170-grain boattail round, composed of incendiary mix, zirconium powder, HE mix, and a depleted uranium penetrator inside a steel cup, encased in a copper jacket. It is designed to defeat most common forms of body armor and explode inside the target, with a pyrotechnical detonation train instead of a manual fuse that sets off the HE filler and incendiary mix, to ensure maximum effect and terminal ballistic consistency. Fired from a 10.3-inch unsuppressed barrel, the Mk 30 round generates muzzle velocities of over 900 m/s, with an effective range of 700 meters. AP-I/HE rounds are marked with green tips.
Mark 30 Mod. 1 Armor-Piercing, Incendiary, High-Explosive, Tracer
A standard Mark 30 round, but with the tritanium alloy replaced with a tracer mix for tracking rounds in-flight and gauging the impact. Marked with a short white tip over the green tip.
Mark 30 Mod. 2 Armor-Piercing Incendiary
A modified Mark 30 round, replacing the HE filler with more incendiary mix, as well as a smaller penetrator and steel cup. Designed to maximize incendiary effect on target, capable of igniting flammable liquids such as fuel or hydraulic fluid to a greater capacity than standard Mark 30. This is considered to be a "special-purpose" round, reserved for offensive forces such as those under TACCOM. Colored with an orange tip.
Mark 31 Mod. 0 High-Velocity Armor-Piercing, Saboted
A 5.7mm sub-caliber penetrator encased in a cup sabot. As the projectile is smaller in diameter and lighter than a conventional round, it is propelled at a higher velocity of roughly 1200 m/s when fired out of 10.3-inch barrel, and the reduced cross section of the penetrator makes it more effective against hard armor. Terminal effects are lessened, although this round is more intended for use against more armored targets such as thin-skinned vehicles or exosuits instead of a standard dismounted infantry unit. HVAP-S rounds are marked with black tips, and weapons firing HVAP-S rounds must have their barrels outfitted with a stellite liner to avoid damaging the rifling with the plastic cup sabot.
Mark 31 Mod. 0 High-Velocity Armor-Piercing, Saboted, Tracer
A specially-designed sabot round with a tracer tail for in-flight monitoring and better impact gauging. Marked with a short white tip over the black tip.
Mark 32 Mod. 0 High-Explosive, Plastic
An experimental thin-shelled round filled with a dense plastic explosive composition and a delayed-action base fuze. The plastic explosive diffuses along the target upon impact and is then detonated by the base fuze, which manipulates the large surface area of the explosive to cause a shockwave to go through a metal (typically steel) plate, causing little bits of metal (spall) to fragment and fly off at high velocity. It is a low-velocity round designed to fight enemies with primitive types of plate armor, with thicknesses that may not be penetrated by conventional munitions.