40mm or 90mm, or maybe even 105mm


Both FRES Specialist vehicle Scout and the new and improved Warrior MICV will be fitted with the CTAI 40mm cannon. There are a number of debates about this, does the cased telescoping ammunition offer enough of an advantage to justify the cost, will we ever field advanced natures, is the calibre too high when everyone else uses 25mm to 30mm and will this unique system provide any export potential but instead of these an interesting question to pose is why an automatic cannon and why not a large calibre systems like 90mm or 105m?

With the Warrior, the weapon will primarily provide supporting fire for disembarked infantry and to destroy enemy MICV. In a typical armoured manoeuvre operation, it will be joined by automatic 7.62mm and 12.7mm machine guns, 40mm GMG, supported by dismounted Javelin anti-tank missiles (we no longer have an under armour ATGW, which is another issue entirely) and the 120mm of the Challenger 2. In addition, indirect fire will be provided by 81mm mortar, 155mm artillery, GMLRS and even close air support from fast jets, Apache and unmanned systems (almost makes one sympathise with the enemy)

In another scenario, like Afghanistan for example, the Warrior might not have 155mm available or 120mm direct fire (at least not from the UK) but have 60mm mortar and the 105mm light gun.

Infantry weapons like underslung grenade launchers, the various tube-launched anti-structure munitions and the new NLAW can also be used.

So from this, it can be seen that it operates in a complex matrix that is ever-changing depending on deployed forces and other variables.

FRES Scout in its traditional CVR(T) replacement role will, in many situations, be operating beyond the forward CR2 where the anti-armour performance will be of greater importance than its ability to suppress infantry, especially given the old Striker/Swingfire combination of anti-armour overwatch will no longer form part of the FRES family. The TRACER programme had this capability and most of the early incarnation of FRES likewise, but it has been quietly dropped.

Another factor worth considering is that both CVR(T), FRES and Warrior have and will be used outside of their neat doctrinal boxes, often acting in the role of the light tank or infantry fire support. I looked at these secondary roles in a number of recent posts and came to the conclusion that in many operations these seem to assume a primary role.

This also opens up the natural questioning of the need for a proper light/medium tank but enough of that for now!

A medium calibre main gun was last seen in UK service on the Scorpion and Saladin, the 76mm L23A1 in the Scorpion was a development of the earlier L5A1 in the Saladin. Ammunition natures included HESH-T, illuminating, smoke, HE, canister and various training rounds. The Scorpion was withdrawn many years ago but the same turret on Canadian Cougars saw service in the Balkans.

In export models, the CVR(T) has been sold with the Cockerill 90mm medium velocity cannon and there were even concepts for a vehicle called the Sagita that Alvis proposed for the US Army Mobile protected Gun System (MPGS) based on an evolved Stomer chassis. Three models were proposed, one with the 76mm L23A1 with twin TOW launchers, another with a two-man turret equipped with the 75mm ARES high-velocity automatic gun and a final variant fitted with a higher calibre weapon, either the Cockerill 90mm Mk III, the Rheinmetall Rh105-11 or a new design from Royal Ordnance.

With other systems and in the context described above the 25-40mm automatic cannon would seem to offer an excellent and relevant set of capabilities and therefore the withdrawal of the 76mm weapon entirely vindicated but in an operation like that in Afghanistan would something similar provide an additional set of capabilities that would make an investment worthwhile?

Javelin has proved invaluable, long-range, highly accurate, portable on small vehicles and powerful but the principal problem is that of cost. At approximately £70k each their use becomes problematical in an extended campaign. There is a view that it doesn’t matter what they cost, if a weapon system can be used to kill an IED emplacer then that is an effective operational and economic use. This is a persuasive argument and from one perspective entirely valid. But we have seen that there is no unlimited pot of gold and decisions in one area of defence have implications in other. Javelin also has a relatively long flight time at range when compared to a gun launched round.

Relying on close air support delivered from UAV, helicopters or fast jets is also hugely expensive and subject to delays caused by both availability and rules of engagement.

Indirect fire support from organic infantry mortars can be extremely fast into action and hugely effective but the lack of precision matures makes them not suited to many situations and adding precision guidance negates many of the advantages of mortars as well. Artillery and GMLRS are also not without their own problems.

When Challenger is not deployed, as in Afghanistan, or there is a need for a higher elevation angle, the largest calibre vehicle-mounted weapon will be the 40mm CTA cannon. Looking into the crystal ball and the future character of conflict, urban environments would seem to be highly likely.

The question therefore is, is there a gap in firepower, somewhere between the 25-40mm automatic cannon and 120mm high-velocity system on the Challenger 2 that is not filled by Javelin, infantry weapons and indirect fire in these secondary roles that seem to be utilised more often?

One of the commenters made an interesting and very valid point about first deciding what you want to do and then go shopping, not before.

The first thing to say is it would not be needed to act as a tank, defend against them perhaps but it would be used more often for fire support and anti-light/medium armour.

Other roles would be immediate fire support, wall breaching, destruction of obstacles and roadblocks, clearing large areas with canisters and numerous others where its large round and very low reaction times would be invaluable. Of course, low reaction times and rapid time between firing and effects appearing on the target would also be achievable by an automatic cannon so the key difference would be the effects on target delivered by a small number of large rounds versus a larger number of smaller rounds.

There might even be a psychological advantage in some situations, a big gun looks scary and the noise has its own impact as well.

Would the advantages offered by a larger calibre main gun on FRES and/or Warrior be compelling enough to negate the cost of introducing a new system?

It is interesting to see how our US cousins look at these things and worth noting that the Stryker Brigade Combat Teams do not utilise an automatic cannon-armed Stryker variant, there is none. Although their doctrine is completely different the Reconnaissance Vehicle is only armed with a 12.7mm machine gun but they do have the Mobile Gun System variant that uses an automatic loading 105mm M68A1E4 cannon.

After initial problems (new systems with problems seems acceptable) the MGS started to receive rave reviews in Iraq and was viewed as a battle-winning system.

The official description for the MGS is;

The Mobile Gun System (MGS) supports dismounted infantry and engages the enemy in close combat in order to clear opposition and permit rapid movement allowing the force to maintain the initiative, defeat strong points, and occupy and/or secure key objectives.

I suspect any criticism of the MGS had more to do with the implementation rather than concept. It only has 18 ready rounds and a relatively complex automatic loader for example and some of the ergonomic issues remain.  The initial stories about not being able to fire on the move or being knocked over by the recoil proved to be completely incorrect.

If we accept that there is a gap, and this is far from certain, there exists a few interesting off the shelf systems worth considering.

The first would of course be the same system as used on the US MGS, this has the advantage of being a mature system with the wrinkles ironed out and obvious commonality with a major ally.

The ASCOD was trialled with this system, the drawings must exist somewhere!

More realistically, the ASCOD Light Tank has been supplied to the Royal Thai Marine Corps. This is equipped with an integrated manned turret with a 105mm main weapon from LIW, now Denel Systems. The main weapon is the 52 calibre GT7 which is capable of firing the full range of 105mm natures available from a wide variety of manufacturers. 105mm is still a hugely popular calibre. An interesting feature of the GT7 is that it doesn’t have a muzzle brake and thus avoids some of the problems with injuring surrounding infantry that such equipped weapons can sometimes suffer from. The GT-7 is derived from the venerable Royal Ordnance L7 with a new recoil system.

The LMT-105 turret, a development of the 76mm Rooikat, is also equipped with a full suite of an advanced set of fire control and electro-optical sensors, is fully stabilised and has a 7.62mm coaxial machine gun.

Other turrets/guns could also be used such as those from Oto Melara HITFACT  or CMI Defence CT-CV

If a smaller intermediate weapon was required the Cockerill 90mm MKIII is still available from CMI and would allow a greater number of rounds to be carried.

The CT-CV is interesting, not because of the Falarick gun launched missile because it also offers a high elevation of 42 degrees for use in urban environments although it only has 15 ready rounds, more would be carried on the vehicle and loaded into the automatic loading system under armour.

CT-CV has been fitted to the General Dynamics Pandur armoured fire support vehicle, General Dynamics of course being the manufacture of FRES Scout and the Polish Anders armoured vehicle has also been integrated with the turret.

When we look at these it does not have to be an either-or, would, for example, 1 in 3 FRES Scouts fitted with one of these turrets offer an increase in capability worthy of the extra capital and through-life cost or are we fine with what we have?

An interesting question.

Newest Most Voted
Inline Feedbacks
View all comments