Weapons

The weapons of the SSRP universe take the form of highly-developed ballistic weaponry for personnel. Multiple manufacturers create firearms for the Sol Defence Corps and a variety of these are available as either standard- or special-issue.

Calibres
The SDC uses several standard calibres in its current weapons arsenal, 2 for long guns, 1 for PDWs, 3 for handguns, and 1 shotgun cartridge. Additional efforts are being made to narrow the selection of cartridges even further in order to better standardize ammunition and make logistics handling more streamlined than it already is.

Casing
All bullet calibres in current usage utilise cased cartridges of strong, thermally-conductive graphene-polymer composite to wick heat away from the weapon. The polymer, built to withstand the extreme pressures and loads that are undergone in an exploding bullet, is specially designed to have similar characteristics in thermal conductivity to brass while substantially decreasing weight. Advancements in strengthening polymers and the increased availability of graphene has made caseless ammunition obsolete in favour of polymer casings. The casing itself contains an inner thermal-conductive layer responsible for transferring heat out of the gun and into the casing, and the outer white shell acts as an insulator. Contrary to brass, freshly-spent casings can be picked up without being extremely hot to touch.

Propellant
The propellant is a volatile block of solid composite high-yield, moderate-burn propellant, with its characteristics tweaked and optimised depending on the weapon and calibre, named XFP (Express Firearm Propellant). XFP has a much higher energy density than smokeless powder, allowing for much higher pressure loads in similar sizes and, as a result, higher-velocity bullets than would be otherwise achievable with conventional propellant.

XFP is safe at proper temperatures and cannot be detonated by an electric spark or via external means; the propellant can only activate when triggered exclusively by the primer.

All these factors combine to create cartridges with much more power and kinetic energy than an equivalent 21st century round. 7x47mm, for example, has a muzzle energy rating of 5,120 J with a 130gr bullet, compared to 3,470 J of 7.62x51mm NATO. This is all accomplished while providing longer range, higher velocity and greater armour penetration capabilities.

7x47mm (.300) / M74
7x47mm (seven-four-seven) is the standard-issue rifle calibre of the SDC, meant as a compromise between previous-generation calibres of 5.56, 7.62 and 6.8. Uses a durable lightweight polymer casing, a solid-block explosive propellant with zero fouling capability, and comes with multiple bullet types and pressure configurations for filling diverse roles.

7x47mm ammunition has an effective range of 1.55 kilometers with a 5.3 kilometer maximum range. M74 Standard has a velocity of 1.1 kilometers/second. The bullet is designed for minimal loss of energy over distance, greatly reducing bullet drop and dramatically increasing its effective range compared to predecessor cartridges.

Due to its polymer casing and lightweight propellant, 7x47mm is also much lighter than predecessors, with the whole cartridge only weighing 133gr (8.6g) with a 105gr FMJ bullet. Almost 80% of the weight of the round is taken up by the bullet only. This does have the minor downside of making the bullet extremely top-heavy, so the primer base is given additional weight to counteract it.

11x80mm (.433) / M433
Anti-materiel rifle cartridge used for heavy weapons such as anti-materiel snipers, HMGs, or small autocannons. Uses the same design and core components as 7x47mm, extended into a larger round. The base variant has an effective range of 2.55 kilometers with a 7.5 kilometer maximum range, with a standard velocity of 1.9 kilometers/second.

10.5x47mm NAVSOC (.413) / M105
An in-house subsonic cartridge designed by the SDC's NAVSOC division, designed specifically for usage in special operations firearms where close quarters stopping power is prioritised for firearms. While it has a shorter range, it is much more powerful up close than 7x47mm and as a result is regarded as the calibre of choice for room clearing and indoor combat.

9x19mm / 10x25mm
These two handgun calibres form the bulwark of the SDC's self-loading sidearms, with 9x19mm being gradually phased out by 10x25mm. Both share characteristics of their 21st century namesakes and templates, but have been modified with 22nd century manufacturing processes as well as adopting the polymer casing and solid propellant employed by all other modern weapons.

10x25mm has been retrofitted from its earlier designs to have smoother recoil and greater penetration than its 21st-century predecessor, ensuring it has a similar longevity of service to it's smaller predecessor.

A12G (12ga)
The standard-issue 12-gauge shotgun round. Present for almost two hundred years, the modernized version of the shotgun shell is optimized for higher efficacy versus armoured targets, as well as coming in several varieties intended for different scenarios.

5.8x35mm (.228) / M58
A PDW/pistol armour-piercing calibre intended as a higher-velocity, penetrating counterpart to trauma-focused pistol rounds. Notably featured on the HSG-37 and MLP-22.

.44 Magnum / M44
This highly venerable revolver round is only used on the RV-94 six-shot revolver. Often regarded as a legacy cartridge it too has received the same modernization treatment as its other cousins in the modern arsenal; however, support for it, as well as revolvers as a whole, is planned for being phased out in favour of pistols. While it is in service, however, it has found a considerable niche for delivering slow but powerful rounds that outmatch even the largest pistol calibres available, delivered in a reliable form factor that has existed for over 300 years.

Technology
In addition to new bullets developed, technology has developed as well to make firearms excel in performance as well as improving standards, reliability, and efficacy.

Pulse-action
A relatively new development in firearms is the widespread adoption of pulse-action firearms. Pulse actions use electric discharge to ignite a bullet primer, allowing the weapon to function without usage of a firing pin and, as a result, minimises moving parts. The recoil mechanisms of pulse-action firearms often have linear alternators built into them to recycle energy emitted from the bullet back into the weapon itself, which can be used towards the firing mechanism or towards any electronics integrated into the weapon itself. Most rifles in SDC service use pulse-action, with their recoil mechanisms augmented by linear alternators.

Modern pulse actions can artifically control the speed of a bolt reciprocating backwards and forwards in combination with the recoil buffer, and as a result can drastically reduce the cycle times of weapons, allowing for a much faster fire rate.

Pulse actions can have their firerate fine-tuned and controlled at will, due to having an electronic action mechanism. As a result, weapons can be adjusted to lower their firerates for higher accuracy, or to increase the firerate to provide suppressing fire. Overheating and ejection malfunctions serve as risks to increasing the firerate of assault rifles, however, so it is often limited to either emergency usage or on specially-converted machineguns.

Pulse action is prohibited in civilian markets where fully-automatic weapons are prohibited or regulated -- concerns about hacking a firing control system to modify a semi-auto gun to fire in full-auto have led to civilian market versions replacing pulse-action with mechanical actions instead.

When initially introduced, pulse actions had severe reliability issues that still haunt some reluctant users to modern day. However, these issues were quickly rectified over the next few years, leading to pulse-action becoming an extremely reliable and efficient firing mechanism for weapons due to having very few moving parts and requiring far less cleaning or maintenance than a mechanical action system.

Artificial intelligence
Newer rifles have artificial intelligence and pairing built into the weapons, pairing a weapon AI to a user. While this AI is not robust enough to act as a personal assistant, it is capable of learning from behaviour. Once slaved to an owner, the weapon can track user's shooting behavior and patterns and make recommendations as to when to reload or advise the user on optimal ergonomics. In addition, a rifle AI can monitor a weapon and determine its mechanical lifespan and durability from changes in the ways a rifle works, including advising when to repair or clean the weapon and when to replace its power cell.

Electromagnetic recoil dampeners
Electrifying a firearm also has the advantage of allowing the usage of electromagnets to replace the recoil spring in recoil control. Not only does this make the weapon have a longer lifespan, it also allows for the user to dynamically adjust the recoil dampening of the weapon. Increasing recoil dampening lowers cyclic rate, and vice versa. In addition, the electromagnets can help to alleviate problems with ammunition, eliminate gaps, and help prevent stoppages and jams.

Gyroscopic stabilisation
In addition to electromagnetic recoil dampening, newer rifles also come with built-in gyroscopes that track weapon movement and work to make sure any recoil is directed directly back towards the shooter. This prevents recoil climb or deviation, allowing the user to continuously focus on the same point and fire without needing to adjust their weapon.

In addition, gyroscopic stabilisation can assist with marksmanship, as the gyroscopes can be adjusted to prevent weapon sway as well, allowing a sniper to keep a mark on their target more easily.

Smart optics
Integration of computers into optical targeting technology and on soldiers has allowed for optics to function with much more than simply aim reticles. "Smart" optics allow for various computations to be made to maximise accuracy as well as minimise friendly fire.

IFF interrogators
Most standard-issue optics in the SDC operate an IFF interrogator system which locks a gun in the event an ally is down the sights, preventing friendly fire if a teammate strafes in front of a shooter. Due to concerns about enemy exploitation, this feature can also be readily disabled with an ergonomically-placed button on most new firearms.

IFF interrogators also have the additional ability of highlighting enemies or vehicles that do not return an IFF signal, allowing easy lock-on to enemy targets. This capability can be further enhanced if the user is wearing smart goggles, which will cooperate with the optic to highlight enemies in viewing range.

Automatic rangefinding
Marksman and sniper scopes have built-in rangefinding systems that automatically calculate for bullet drop, windage, and target movement, and a built-in artificial intelligence attempts to predict a target's next moves based on the surrounding environment, and adjust the aiming reticle accordingly to make sure a bullet fired will almost always strike its target. Snipers can even activate automatic trigger pull on their rifles, which automatically fires the weapon if the reticle lines up perfectly with the target. For obvious reasons, the marksman community frowns on this practice and regards it as a crutch in shooting; however, in life-threatening situations, it is often used to rapidly take down a target.

Multi-spectrum optics
Some models of smart optics feature a screen able to project itself over the optic. This screen can switch spectrums to allow the shooter to see in infrared, ultraviolet, night vision, or even provide x-ray vision. Overlays on the screen can be toggled on and off to allow optics to display various other information, ranging from mundane such as compass directions, to practical with highlighting body armour thickness and weak spots on enemies.