The 6.8mm Elephant in the Room

The United States Army has made the biggest change in a generation to its small arms fleets by replacing its standard infantry rifle (the M4) and Light Machine Gun (SAW) with a 'Next Generation Squad Weapon' (NGSW) multi-calibre system based on a new 6.8mm round with high-performance technology to be more lethal at greater range. Some NATO governments are scratching their heads about what this means for the bedrock of NATO interoperability.

This decision butts up against three important contextual factors:

1. More than two years of war in Ukraine has seen an unprecedented focus on the Russian threat and subsequent multi-lateral gifting programmes to arm Ukraine, and emergency NATO memberships for Sweden and Finland.

2. The 5.56mm 'SS109' round has been the cornerstone of NATO interoperability since 1980, when it was adopted by most NATO countries, while a few influential members have recently procured new 5.56 assault rifles including France, Germany, the Netherlands and the UK.

3. Since the drawdown in Afghanistan, there has been a growing movement questioning the effectiveness of 5.56 on the modern battlefield.

Putting aside the classified details of the original US Army requirement for the Next Generation Squad Weapon (NGSW) programme, the Americans took a logical approach: start with the threat (the target) and work back to the weapon (the ammunition) and finally the delivery platform (the rifle/gun). This may sound obvious, but the reality is this approach is truly not the norm for military small arms procurement with NATO governments for a variety of reasons.

It is commonplace for the choice of ammunition nature not to be central to the requirements simply because in-service ammunition natures have a very long service life - it is hard to change them.

This article explores the major implications of the US Army's NGSW programme to future NATO small arms procurements to both dispel some myths and assist the NATO community in understanding the situation and the NGSW.

Show us the money!

In 2017, Lt Gen Mick Bednarek testified on the issue of what happens when a 5.56 round hits someone with body armour to a Senate Armed Services Committee Hearing on small arms (Verger, 2024):

"The US is facing adversaries with L2-3 body armour that precludes our lethality…regardless of range."

"Our capability to eliminate this threat at medium or long range is almost gone, so we must have small arms systems that can stop and can penetrate that increased enemy protection."

"I think the US Army universally realizes that the 5.56 bullet can't defeat Russian body armor."

In the same article, Col Jason Bohannan (Programme Executive Office [PEO] Soldier, US DoD) is quoted referring to the NGSW programme:

"…people get myopically focused on body armor…but there's a series of target sets in the battlefield that will exist for 10 years. And we're trying to balance all of that to put [the] US Army [and the DoD] at large, in an advantageous position."

Fast forward to 2022 when the US Army determined the old standard to be inadequate for the modern battlefield and disrupted the foundation of NATO interoperability by introducing two new squad weapons based on a new ammunition cartridge.

Before we get into the detail here is a big caveat up front - the US 6.8mm GP projectile (the XM1186) is owned by the US Department of Defence, while the hybrid case - the key component to achieving the high velocity that delivers the lethal punch for the NGSW- is owned by American producer SIG Sauer Inc.

Therefore, if NATO governments want to know specifically what this projectile does, they should dust off their bi-lateral defence sharing agreements and speak to their US counterparts; but the capability behind NGSW comes from the hybrid cartridge.

The SIG Sauer hybrid high performance cartridge is a lighter brass-steel composite that allows increased loads and delivers approximately 20-25% more barrel pressure and therefore muzzle velocit...