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Assistant gunner loads Carl-Gustaf M4 with High Explosive round HE 448

Accuracy meets simplicity

6 min read + Video

A new high-explosive round and a sophisticated fire control device have made our Carl-Gustaf® system more effective than ever, while maintaining the ease of use that gunners love.

A ground combat squad is out on patrol in an urban combat zone. They’re carefully making their way forward when one of the team suddenly spots an enemy troop carrier moving behind debris in the distance.

With adrenaline rushing through their veins, the squad’s fire teams scramble into position to engage the enemy.

Our Carl-Gustaf recoilless rifle is ideally suited for such intense combat situations. Light-weight and easy to operate, its wide range of rounds make it a devastating threat to targets ranging from Main Battle Tanks through to dismounted troops.

But recently our engineers wondered if the system could be even better. What if it could offer greater accuracy, range and effectiveness without compromising on ease of use? What benefits would that bring to users in the field?

Special Forces with Carl-Gustaf M4 and FCD 558

The result of their efforts are several enhanced capabilities to help armed forces keep up with the evolving threat. The most recent additions in this regard are a new High Explosive round and an improved Fire Control Device. When used in combination, the Munition will communicate the round type and propellant temperature to the Fire Control Device and receive target data and fuze settings in return. The Fire Control Device will automatically calculate the ballistic settings taking into account round type, propellant and ambient temperature along with target distance and then set up the trajectory for the operator. This is made possible by introduction of a two-way communication interface for the Carl-Gustaf M4, designated “FireBolt”.

“In high stress situations where there is pressure on the fire team to perform, you want to make the firing process as simple as possible,” says Saab Product Manager for Carl-Gustaf, Karl Edström. “You also want the highest probability of a hit with your very first shot. This new combination of a smart round and an advanced fire control device helps you achieve both of those objectives and increase your chance of mission success.”

The new HE 448 round

The new round, which has the designation HE 448 is a major improvement compared to its predecessor the HE 441, which itself remains an industry leader. Like its forerunner, the HE 448 is a high-explosive round designed for use against enemy forces such as dismounted troops, troops in defilade, and soft skin targets including vehicles. The HE 448 fuze allows fire teams to select either direct-fire mode, in which the round impacts on the target, or air-burst mode, where the use of a timer allows it to be detonated above the target.

Carl-Gustaf ammunition High Explosive round HE 448
HE 448

However, the new round takes accuracy, range and effect to the next level. Replacing the mechanical fuze with a small electro-mechanical one has helped reduce weight, meaning the round leaves the barrel with higher muzzle velocity, increasing both accuracy, engagement time, and range. While the HE 441 was accurate out to roughly 1300 metres, the HE 448 is able to engage targets beyond 1500 metres.

At the same time, the fragmentation of the round is radically different from the HE 441. While its predecessor contained 800 steel balls, the HE 448 contains some 4000 tungsten pellets. The result is more fragments, greater dispersal and an increased effectiveness, even in situations where the enemy is wearing body armour.

The weight of the round, which at 2.7 kilograms is about 0.5 kilograms lighter than the HE 441, is good news for the overburdened modern infantryman.

A lethal combination

Karl Edström explains the HE 448 achieves optimal results when it is combined with the new fire control device, the FCD 558.

Set to become the standard fire control system for the Carl-Gustaf system, the FCD 558 can be easily fitted with a standard optical sight via a picatinny rail. While the old fire control system was fully mechanical and relied on interchangeable range knobs, the FCD 558 is electro-mechanical, allowing for direct communication with a chambered round.

When an HE 448 round is chambered in a Carl-Gustaf M4 fitted with an FCD 558, the two components are able to exchange information. The round identifies itself to the FCD and communicates propellant temperature  ­– a crucial parameter in accurate targeting.

Using a toggle on the FCD, the gunner is able to choose either direct fire or airburst, and this information is electronically communicated to the fuze inside the round before firing. The gunner uses the same toggle to enter the range to target. Equipped with information on range, round type, propellant temperature and the required mode, the FCD’s ballistic computer calculates the best possible trajectory to achieve success. When this accuracy is combined with the increased lethality of the HE 448 round, the result is devastating effect on the enemy.

FCD 558 set on airburst 980m with HE 448

Thus the workload of the Operator and the Assistant gunner is significantly reduced, while the flexibility is increased. The Assistant Gunner no longer needs to manually set the fuze and the team can deal with fluid situations effectively. For example, a fire team might decide to switch to air burst mode if a vehicle that was previously in the open drives behind an obstacle.

“We wanted to provide fire teams with increased functionality and accuracy, but we didn’t want to increase the complexity of firing,” says Karl Edström. “While the FCD 558 is more technologically advanced, you don’t experience that as the gunner. You just get better results when attacking the enemy.”

Carl-Gustaf M4 with FCD 558
Carl-Gustaf M4 with FCD 558

Introducing Firebolt

It should be noted that the FCD 558 can be used to fire legacy Carl-Gustaf rounds. Likewise, the HE 448 can be fired with the legacy Carl-Gustaf fire control device (although not in air burst mode).

The combination of the new FCD with rounds capable of communication has proven very effective. New rounds with added capabilities are on the roadmap, and the communication interface – designated “FireBolt” – may even be introduced on legacy rounds, to enable communication with the FCD 558 Fire Control Device and Advanced sights.