A new NATO calibre for assault rifles?

SIG SAUER welcome. Source: Picture Alliance, Lisa Marie Pane

By Dr. Martin Krause //

On 19 April 2022, the US Armed Forces declared with regards to the Next Generation Squad Weapon tender (NGSW) to procure new 6.8×51 mm calibre assault rifles and machine guns from SIG Sauer for the US Army. The purpose is to replace, at least in part, the M4 assault rifle and the M240 and M249 machine guns with the XM5 and XM250 respectively. Does this decision have the potential to fundamentally change the entire weapons and ammunition logistics of the NATO countries in the field of military rifles?


In 2017, the US military launched the Next Generation Squad Weapon programme (NGSW) to replace the M4 assault rifle and the M240 and M249 machine guns including ammunition for the two NATO calibres 5.56×45 mm and 7.62×51 mm. The controversial discussion about the performance of these two calibres is decades old and is based, among other things, on aspects such as recoil, cartridge weight, range, target impact, etc. Most recently, the penetration performance of the smaller NATO calibre 5.56×45 mm was considered too low, since ballistic body protection in particular is becoming more sophisticated and more widespread. In order to find a sensible compromise in the form of a new medium calibre, the tender specified 6.8 mm projectiles and called for the corresponding cartridge to be developed together with the weapons.

Of the remaining participants, SIG Sauer finally won with the MCX-SPEAR and the LMG-6.8 as well as the SIG 6.8×51 mm hybrid cartridge, which consists of a brass case with a steel base. Previously rejected competitors pursued concepts based on polymer case cartridges or telescoped ammunition. Furthermore, the XM157 Optronic from Vortex was chosen, which, in view of the integrated ballistic computer and sensor packages, represents a clear step towards a digitalised rifle respectively smart rifle. A total of up to USD 1.4 billion is to be invested over the next 5 years.

Significance for Germany and Europe

The current tender for a new assault rifle for the German Armed Forces has been running for more than half a decade, with the two manufacturers Heckler & Koch and C.G. Haenel still in the game. The technical evaluation of the calibre 5.56×45 mm calibre weapons was followed by a legal dispute, of which the outcome is still unclear.

Especially against the backdrop of the new geopolitical situation, a much closer transatlantic cooperation in the field of defence seems reasonable. In this respect, one might ask whether the German Armed Forces will procure a new 5.56×45 mm calibre assault rifle for the next decades when the USA, the by far most important NATO ally, already considers this calibre too small, too weak and outdated.

As a theoretically possible scenario, the time until the introduction of a new 6.8×51 mm calibre weapon could be bridged by a possible midlife upgrade of the currently used G36. Admittedly, this would also require certified ammunition of several manufacturers to be available on the market in the foreseeable future. The calibre discussion will certainly be reopened with any further future assault rifle or machine gun procurement in Europe, and there is a possibility that a new NATO standard calibre will de facto emerge to complement the existing ones.

However, the consequences of the NGSW tender for Europe are not limited to the arms manufacturer sector. European ammunition producers will also have to develop and certify their own 6.8×51 mm ammunition. In addition, it is necessary for European optronics manufacturers to consequently extend their product portfolio in the direction of digital aiming devices, for example including laser rangefinders, ballistic computers, and digital display overlays. The goal is to ensure a high hit accuracy even at a large combat distance. And last but not least, ballistic body armour must be optimised at the same time so that soldiers of European armed forces are protected adequately.

Technical challenge

Currently, no German manufacturer offers either a military 6.8×51 mm calibre gun that is ready for series production or the related ammunition. And very few producers in Europe will even have worked with this calibre to date.

Reliable military weapons with a new calibre as well as the related ammunition for them cannot be developed overnight and their design and testing require considerable resources. Simplified, one could imagine scaling up an existing 5.56×45 mm or 7.62×51 mm calibre rifle and converting it to the new calibre. However, this initially comes with a large number of technical problems for which the new weapon still needs to be adapted and optimised in detail – in some cases at considerable expense. These include, for example, the pressure curves in the cartridge and barrel, the highly dynamic behaviour of the gas loading mechanism, as well as the changed loads on the overall structure. In this respect, a military rifle for a new cartridge should ideally be a new development, which can certainly be based on proven concepts within the framework of a product family. One sets one’s own standards in particular when the weapon and the ammunition are initially designed to work together as a system.

New opportunities

If new 6.8×51 mm calibre guns, the corresponding ammunition or related optronics are put out to tender in Europe in the foreseeable future, the cards will be reshuffled among the potential manufacturers. The same applies in the event that the current tender for the Bundeswehr’s new assault rifle might actually be relaunched. In concrete terms, a reshuffled deck means that smaller manufacturers or foreign manufacturers, who used to be in the second row behind the established players with regards to large tenders, will then have a good chance of positioning themselves.

The key to success will be to develop and test the new technology faster than the competition, in other words to implement the necessary innovation quickly. However, outrunning the competition by shortening development cycles will only be possible if empirical knowledge, experimental testing, and new methodology are combined in an intelligent way throughout the development processes. This is done, for example, through the consistent use of modern simulation technology in cooperation with collaboration partners from research institutes and universities. Lengthy experimental trials can thus be shortened, and experimental data sets can be evaluated with high-quality machine learning algorithms. Furthermore, new differentiation potential arises from the use of new materials combined with innovative manufacturing processes such as 3D printing. The same holds for modular and integrated sensor technology for the optional digitalisation of a rifle.

Those who recognise this strategic opportunity and know how to exploit the disruptive potential of the situation can win the race for future orders and the associated market position. For the coming decades, the Ukraine war puts the focus back on national and alliance defence in the scenario of a symmetrical war, for which the 5.56×45 mm calibre is considered potentially too weak. The shift to a larger and more powerful calibre is not only due to the increasing use of ballistic body armour. Also the significantly improved aiming devices create new opportunities. If manufacturers see a market potential here, they should start their activities soon because of the long development times. At ACTRANS, as a management consultancy with a focus on technology and innovation, we support our clients in terms of aligning their product portfolios, development processes and capabilities, as well as technologies with growth and innovation.