Paper: Automatic Cannons and Ammunition in Infantry Fighting Vehicles

Author wants express his thanks to MSI Magazine for their support in the preparation and publication of this paper. 

http://www.milscint.com/en/

57mm Autocannon Turret from Russia

Russian 57mm AutoCannon Turret:

The Future Caliber or Relic from the Past?

The Franco-Russian cooperation for an IFV was recently revealed. It's an 8x8 vehicle called Atom.

One of the features that got quite a bit of attention is the 57mm main gun in the two-men turret.

The turret is called AU-220. It's been initially developed as an upgrade to the PT-76 amphibious tank to replace its 76mm main gun and old turret.

An upgraded PT-76 is shown with the 57mm AU-220 turret.

57mm Gun

The 57mm gun that's also used in Atom 8x8 is basically an Anti-Aircraft gun used in S-60 towed AA system. The gun was developed in 1950's.

In the AA configuration the gun is fed by 4 round clips. The same gun in the S60 AA mount is shown below.

The same cannon also used in ZSU-57-2 SPAAG vehicle.

The cannon uses 57x347mm semi-rimmed ammunition. The image below shows the 57mm ammunition vs the Bofors 40x365 ammunition.

The gun is recoil operated. Rate of fire is 105-120 rpm and the muzzle velocity is around 1.020 m/sec. It has a barrel length of around 4.4m.

The effective firing range against ground targets is 4km's.

AU-220 Turret

The turret is of Two Men configuration and weighs around 3.5 tons. The main armament is the 57mm rapid fire cannon.

The gun has a new automatic loading capable ammunition feed system that houses 20 ready-to-fire rounds as shown below.

The turret basket has a powered 73 round ammunition carousel that provides ammunition to the linkless feeder above.

The 57mm gun with the AP round has a penetration capability of 130mm of Steel at a range of 1.000m. I would expect the penetration would be much better for the huge 57mm caliber. 

The 35mm APFSDS round has 120mm penetration at the same range. 

This does not mean a lot at first glance, and you can think that the 57mm is still better than 35mm. 

But when you think about the 35mm round doing all this with only 22% of the mass of the 57mm, one thinks that the 57mm caliber needs new ammunition in the APFSDS type to become a serious contender in the medium caliber market.

©WarfareTechnology 2014

KMW IWS35 Remote Turret

KMW's 35mm Remote Turret

IWS 35

KMW has an ongoing development for a Remote Turret. The turret is called IWS35.

IWS35 is armed with a 35mm Bushmaster II Autocannon and a .50cal (12.7mm) Bushmaster Heavy Machine Gun. Both weapons are products of ATK.

Instead of a traditional use of a 7.62mm machine gun; the selection of a .50cal chaingun  as a coaxial gun is quite interesting. This leads me thinking that the concept of operation for this turret is based on frequent use of the 12.7mm machine gun. The lethality of the 12.7mm gun is way higher than a 7.62mm gun, thus unless the utmost power of the 25mm cannon is not needed, the operator will rely on the .50cal. machine gun.

The turret is made of welded aluminum. It has electric drives for traverse and elevation and also dual axis stabilized sights for gunner and commander.

The sights seemed to me the same units used in the German Puma IFV's turret as shown below. As far as I remember these are from German company Carl Zeiss. Both sights have day TV and thermal imagers along with laser range finders.

 

Sights in Spz Puma Turret

 

Sights in IWS35

  The weapons in IWS35 turret has different elevation limits. The .50cal chaingun can elevate up to 65 degrees; whereas the 35mm cannon can elevate up to 35 degrees. The turret drives are developed by Moog.

The ammunition for the main gun, 35mm Bushmaster III is fed from a linkless magazine developed by Meggitt. I could not find any information whether the main gun ammunition can be replenished from inside the vehicle or not. The ammunition capacity for the main gun, which is also very important, remains to be seen.

The ammunition for the .50cal machinegun is fed from an ammo can located on the left side of the gun. It seems it can only be replenished from outside.

The IWS35 remote turret seems to be an interesting addition to the remote turrets market with an important distinction of fire power: the Bushmaster III 35mm.

Oerlikon 35mm Revolver Cannon

35mm Cannon Story continues:

Oerlikon/Rheinmetall

35mm Revolver Cannon

Our story for 35mm cannon continues with Rheinmetall's - formerly Oerlikon's - 35/1000 Revolver gun.

This gun is mainly used for air defense. THe interesting feature is the Revolver principle:

In most simple terms the principle is basically the same as your old Six Shooter.

The cylinder including the chambers - aka revolver- rotates counter-clock wise, the chamber at 6 o'clock position lines up with the barrel. 35/1000 cannon has 4 chambers in the revolver as shown above.

Another image showing the principle:

The 35/1000 cannon is gas operated with a rate of fire of 1.000 rounds per minute!

35/1000 gun chambers 35x228mm ammunition and uses linkless ammunition.

The gun is the business end of the German SkyShield C-RAM (Counter Rocket/Artillery/Mortar) system. 

Gun data:

Caliber: 35mm

Length: 4.11m

Weight: 450kg

35/1000 gun in the SkyShield Remote Turret has been integrated on a Piranha III, Piranha IV, Boxer vehicles as a mobile air defense vehicle solution.

 

ATK Bushmaster III Automatic Cannon

Bushmaster III 35mm Cannon

For today's threats as well as future's??

Bushmaster III is the biggest and baddest member of the Bushmaster Chainguns that is available for integration. Although there is Bushmaster IV 40mm cannon, it is, as far as I know, in prototype stage.

Bushmaster III is a electric driven, link-fed automatic cannon that can be employed either as a 35mm or with changing the barrel and forward feeder assembly can chamber SuperShot50, 50mm ammunition. There are some works going on for the linkless feed Bushmaster 35mm; however the in-service guns are link-fed.

The specification for the Bushmaster III is roughly:

In order to better see the differences between 25mm M242, 30mm Mk44 and 35mm Bushmaster III, here is a short comparison:

And here is another image that compares the sizes of M242 25mm, Mk44 30mm and Bushmaster III autocannons:

Just looking at the size difference between the M242 25mm Bushmaster, you can see that Bushmaster III is a monster.

However, this monster has also quite a strong bite as well!

Let's look at the High Explosive (HE) ammuntion:

The 25mm HE projectile has a mass of 180 g.

The 30mm HE Projectile has a mass of 362 g.

The 35mm HE Projectile has a mass of 550 g!!

Just look at the HE difference and imagine the destructive effect of the 35mm HE!

For an IFV vehicle, the real bite of the gun comes thru the armor piercing capability versus armored threats.

The lethality performance against armor plate is usually expressed when the projectile is not hitting on a vertical plate, but impacting on a sloped armor as shown in the image below. The commonly accepted method is expressed as 60 degree obliquity.

 

    

 Now keeping this information in mind, the graph below shows the penetration capability of 25mm, 30mm and 35mm Armor Piercing Sabot rounds:

Some highlights from the graph above:

i. 30mm has ~30% more penetration than 25mm.

ii. 35mm has ~60% more penetration than 25mm.

We should also keep in mind that:

i. 25mm AP round tracer burns-out at around 2000 meters, thus seeing fall-of-shot beyond 2km becomes really difficult.

ii. Due to trajectory and velocity decrease, 25mm round's accuracy drops down considerably beyond 2km's.

iii. However, with the 35mm, accurate firing beyond 3km is possible and proven by the Dutch gunners from CV9035 in Afghanistan.

In terms of lethality, 30x173mm caliber is performing quite good against today's battlefield threats like BMP-3.

However, TNO's 30mm vs 35mm comparison document states that:

One other important issue for Bushmaster 3 turret integration is the ammunition capacity.

Before going into that, we should better have an idea of the size of 35mm ammunition. I believe this can help:

Now, getting back the issue of ammunition capacity:

i. Belted 35mm ammunition would be really difficult to handle during loading because of the weight and size of the belts of ammo.

ii. Linkless feed systems can be an appropriate alternative for 35mm feed systems. I will explain Linkless Feed later on.

iii. The number of ready to fire ammunition is very important, ie. CV9035 has a total of 70 rounds of belted 35mm ready-to-fire, which is not bad.

However, an IFV turret with Bushmaster III and 100 ready-to-fire rounds would be a real winner.

iv. For a turret that is armed with Bushmaster III, the First Round Hit Probability (FRHP) would be especially important. Because you no longer have an ammo capacity such as Bradley's 300 rounds of 25mm. So for 35mm, your fire control system should make every shot count! 

©2014 Warfare Technology

CV9035 Afghanistan and some experiences

CV9035 MkIII

&

Experiences from Afghanistan

 I've been surfing thru Military Photos (www.militaryphotos.net) and came across a thread on Danish CV9035 MkIII IFV's and some interesting remarks on Afghanistan.

An Interesting remark on terrain in Afghanistan:

"The terrain in Helmand is very...VERY... rough. We had a couple of Piranha's that got stuck in some ditches. We had to get EOD to blast the front wheel free from the chassis using explosives.

The M113's are much more suited for the terrain."

CV9035 35mm HEI rounds comparison:

Shell Mass (HEI)
25x127mm : 185g (Bradley, LAV 25 etc.)
30x173mm : 360g (EFV, Puma, CV9030 etc.)
35x228mm : 550g (CV9035)  

 

Remarks from a CV9035 DK gunner:

"Well i have confirmed hits of over 3000+ meters.. And another guy in our company have even better than me =) and that was during moving.....

We have a " smörgåsbord " of ammo..
All from FAP , HE , KETF ... "

and I've heard from other sources that the CV9035 with its Bushmaster III 35mm gun has acquired quite a fear in Afghanistan among Taliban. What I've heard confirms the above remarks, such that when a CV9035 appears, the insurgents quickly disappear. Because CV9035 can hit mansize targets at 3.000m.

Danish CV90 fleet in Afghanistan:

The Danish Army has, for the first time, deployed a fleet of ten BAE Systems Hägglunds CV9035 infantry fighting vehicles to Afghanistan.

The deployed vehicles feature several upgrades, including BAE Systems L-ROD bar armour, Barracuda camouflage, and software modifications to the vehicle's computer system to enhance battlefield readiness.

In addition, extra power supply for the electronic counter measures system and an additional IR camera for the driver covering the rear of the vehicle were also included in the upgrades.

The vehicles received major upgrades after their arrival in Camp Bastion, Helmand province, in mid February.

An armoured infantry company of the ninth Danish battlegroup will operate the new fleet of CV9035s to serve with the International Security Assistance Force.

The vehicles will operate alongside tracked M113G3 and wheeled Piranha IIIH armoured personnel carriers, and a platoon of Leopard 2A4 main battle tanks.

Some nice images of Danish CV9035

 

©2014 Warfare Technology