Caseless Ammunition

Caseless has been the mainstay ammunition type for the majority of kinetic weaponry since the early-2000s. While the technology was demonstrated as far back as the 1960s, issues with stability of the propellant and expense led to the project being shelved. It was not until the development of the M-4 Light Rifle that caseless ammunition resurfaced as a viable project. 

At the time, the Escean military was in the process of a serious restructuring, with its policies focusing more on mobility and lightness. State-owned Alliance Technologies was given the task of developing a rifle using caseless ammunition for widespread adoption. With cheaper and more advanced production methods available, the result exceeded so many expectations that caseless was ultimately chosen by SAPROC (Senatorial Arms Procurement Committee) as the new ammunition type for the Escean military.

Within a decade, all Escean cased ammunition types were switched out for caseless variants, and new weapon designs soon followed to better incorporate them. Today, the modern firearms and weapons systems of all industrialised human nations - including those of non-electromagnetic vehicular units – and numerous alien militaries utilise caseless ammunition. 

While there were many detractors within the military resistant to change, caseless ammunition offered numerous benefits. Many of the issues cited by the cynics were corrected with minor changes, allowing the ammunition to perform under the same or harsher conditions with additional benefits. Much like adding extra grains to cased ammunition, the volatility of caseless HTIP upon detonation is adjustable, giving the bullet inside greater velocity or range. Some short-barrel weapons use this to retain their compactness without sacrificing velocity. 

Heat – The chief concern with caseless ammunition lay in its ability to withstand excess heat resulting from sustained or frequent fire – since the bullet is contained entirely within its propellant, there is no metal casing to act as a sink and remove excess heat during extraction. The solution was an HTIP mixture with a higher ignition temperature, doubling as an insulator and preventing waste heat leading to cook-off. In comparative tests, the caseless design was able to withstand a slightly higher ambient temperature, as it did not accumulate heat as quickly as exposed metal.

Stability – Mid-20th century attempts at caseless failed in part because the propellant failed to withstand the strain of loading during rapid fire. In some tests, the propellant crumbled under stress or suffered because of environmental conditions. Modern HTIP propellant is bonded on a molecular level, allowing it to withstand even the highest rates of fire. Weatherproofing consists of a hydrophobic nanohair coating, whilst the mixture itself can comfortably perform in the hottest desert or the icy depths of space.

Weight – Arguably, the biggest benefit of caseless ammunition is the significant reduction in weight. Eschewing a metal case reduced the overall weight by 60%, allowing a soldier to carry more rounds. By switching to a telescoped design, in which the bullet is enveloped partially or entirely within its propellant, the designers also reduced the dimensions of the round. Magazines were able to contain more rounds in the same amount of space, further boosting the amount a solider could carry compared with cased.

Covertness – Since there is no ejected case, special forces units can engage without worry of post mission identification through ammunition left behind, or the need to police up spent cartridges. The lack of an ejection port (other than a manually operated one for remedial action), also lends itself to concealing the shooter through additional noise and flash reduction when using a suppressor. This offers another benefit in protecting the weapon internals from dust and dirt ingestion. Aside from the bullet, the only physical components of the round that leave the barrel are fragments of the plastic retainer cap.

There are two variations of caseless ammunition in use. 

Full-Wrap is the most widespread variation and fully encloses the bullet within a cylinder of HTIP. The base of the cylinder contains a receptacle with a primer cap, which detonates via the electrical initiator or hammer of a weapon and is used to propel the round through the plastic retainer cap holding the bullet in place. As the bullet fragments the retainer and leaves the cylinder, the HTIP detonates, propelling the round to its maximum velocity whilst simultaneously cycling the bolt. 

Half-Wrap is less common and typically used in sidearms and SMG-type weapons using pistol cartridges. In this variation, the bullet is only partially covered by HTIP, leaving the tip exposed. A primer cap sits in the base and the mechanism of firing remains the same, save for the fragmenting retainer. Half-Wrap is common in civilian marketed rifles as it reduces the overall power of the ammunition. Likewise, in military applications it was applied to reduce over penetration risk in the aforementioned weapons, as they were commonly employed in counter-terrorism operations involving hostages or sensitive environments.

As some types of caseless ammunition can appear similar at a glance, all caseless ammunition is marked with a coloured band to determine its application, and an identification code to denote what weapons are compatible. Military cartridges use a red band, whilst civilian ammunition uses a blue band.