We will be attending several tradeshows this month. Come and see our team any time at our booth:

– INFOPOL in Kortrijk, Belgium, from 23 through to 25 April 2024

– POLSECURE in Kielce, Poland, from 23 through to 25 April 2024


Rifle modularity:

Maximising the FN SCAR®’s lethality for the soldier

Being able to adapt a personal rifle to suit a soldier’s body size, firing preference and mission is critical in ensuring that the weapon is as lethal as possible. It is for this reason that modern rifles must be modular, ensuring that soldiers can adapt their firearm for whatever challenges they face, as well as being extremely reliable in adverse conditions. In this article, we explore how FN Herstal manufactures highly modular rifles, such as the FN SCAR®, to suit the modern soldier.

In the past, every soldier’s rifle was exactly the same, despite the fact that each soldier was different in some way, whether that was size, height or even whether they were left-handed or right-handed. Because of this one-size-fits-all approach, many soldiers found it difficult to fire a rifle properly, which impacted their effectiveness on the battlefield, particularly when it came to accurate firing against targets in prone, sitting or standing positions.

In recent years, manufacturers such as FN Herstal have understood that no two soldiers are the same and that a one-size-fits-all approach to rifle design is no longer adequate. Rifles must be able to adapt to their user, fitting around their particular physical attributes or mission requirements to enhance the firing experience. This ensures that soldiers are able to fire more effectively in multiple positions and still adhere to marksmanship principles, ultimately enhancing the effectiveness of a squad.

What elements of an FN Herstal rifle – particularly the very popular FN SCAR® – can be adapted to the user?


The buttstock is where the soldier connects to the rifle when firing, and in most firing positions this will be placed into the shoulder and the cheek will rest on it to aim. Without modularity, a soldier can struggle to position the rifle correctly to aim down the sights for an accurate shot and this can add to user discomfort. Greater discomfort means less accurate firing.

“Maximum user comfort
means high-precision shooting”

Across all the FN SCAR® rifles, FN Herstal has added significant modularity to the buttstock to address these common challenges. The FN SCAR® assault rifles come as standard with a foldable, adjustable buttstock with six positions for length (which accounts for varying arm lengths) and two positions for the cheek rest that significantly improves user comfort and sight picture.

A range of additional buttstock configurations are available to account for special user requirements, including an offset buttstock for use with a visor helmet or soldier-specific equipment. This ensures that all FN SCAR® rifles can support unique user preferences, including how they hold/fire a rifle as well as how they place accessories such as optical sights.

Ambidextrous controls

In the past, many soldiers have had to learn to hold, operate and fire rifles right-handed, even if they were left-handed, which has impacted the quality of marksmanship. Older rifles would have controls – such as safety switches, cocking handles, fire selectors and magazine release catches – on the right side and empty cases would also eject from the right, meaning that holding rifles left-handed would be almost impossible.

Modern rifles such as FN Herstal’s SCAR® no longer have these challenges and feature ambidextrous controls – meaning that rifle controls are on both sides – that allow users to hold the rifle in their dominant hand, whether that is left or right. And because of a deflector fitted to the rifle, spent cases will eject either forward or laterally and not towards the user.

These features significantly improve soldier marksmanship as well as reduce training time, as personnel do not have to build muscle memory on their weaker sides.

“Ambidextrous controls
improve soldier marksmanship
and reduce training time

Attachment points

Unlike older rifles that may have only used an iron sight for firing, modern rifles such as the FN SCAR® now leverage a number of attachments/accessories to aid user operation and mission effectiveness, including day/night sighting systems, laser designators, lights, aiming units, grenade launchers and foregrips. Rifle attachment points allow these accessories to be fitted by the user with ease dependent on the role of the soldier, their preferences, as well as the mission that they are performing.

As part of this accessory modularity, rifles such as the FN SCAR® utilise Picatinny type rails – a military-specific attachment system that is codified in the MIL-STD-1913 military standard, as well as the NATO Standardisation Agreement STANAG 4964.

The FN SCAR® features Picatinny type rails on the 12, 3, 6 and 9 o’clock positions on the rifle, as well as a continuous rail across the entire upper receiver. The latter feature allows operators to use a day sight in conjunction with an add-on night vision sight that fits in front during night operations. This means a soldier does not have to take off their day sight during the night and this also doesn’t impact the sight’s zero (the sight’s aiming point alignment), which would occur if it was removed. An additional advantage of the continuous top rail is that the optic is not placed on a removable handguard, which will develop some play over time, resulting in a loss of zero.

“A continuous, full-length top rail that accepts both day and night sights in-line
ensures that the zero of the sight remains unchanged”

Interchangeable barrels and calibre modularity

A rifle’s barrel length and calibre will have a direct impact on its effectiveness in various combat roles. There are times when shorter barrels are preferred, while other times a long barrel and larger calibres will be required. For instance, during urban operations, a short barrel is an optimum solution as engagement ranges are short and mobility will be critical in confined spaces. In other scenarios where long-range engagements are preferred and accuracy is paramount, a long barrel with a calibre such as 7.62x51mm will be a better choice.

Being able to swap out the barrels easily, without sending the rifle back to an armourer, is essential for modern armed forces where combat missions can vary from day to day. This also saves costs for the customer, meaning that they do not have to buy multiple rifles with different length barrels, which can add to procurement costs.

“Interchangeable barrel lengths reduce initial cost”

The FN SCAR® series of assault rifles, available in two NATO calibres, can be fitted with various-length barrels depending on the missions and roles being performed. The choice of different barrels gives far more flexibility to the user depending on their mission requirements, and a conversion kit is also available to allow customers to change the weapon’s calibre from 7.62x51mm NATO to 5.56x45mm NATO where required. The barrels can be swapped in less than five minutes and requires no adjustment and no specific tools.


A soldier’s lethality is centred around the use of their personal weapon, and the better they can utilise this, the more lethal they become. The increasing modularity and reliability of modern rifles – including FN Herstal’s highly modular FN SCAR® rifles – means that soldiers’ lethality has significantly improved, and they are better able to employ the weapon in combat situations. Rifle modularity is allowing soldiers to easily adapt their weapons to aid comfort levels and firing preferences, as well as the mission they are performing – contributing to overall mission success.



Any questions or advice? Get in touch with our team of experts.