Royal Ordnance 105mm Improved Weapon System

[ChieftainWarrior]

Hi,

I've been looking into the Royal Ordnance 'RO2004' light tank design that was built in the late 80s/early 90s; and am now looking for more information regarding its armament.

The tank was armed with a 105mm L7 derivative, called the Improved Weapon System (IWS).

Supposedly it had:
- A rifled barrel of Electro-Slag Refined (ESR) steel fitted with a fume extractor, thermal sleeve, horizontal sliding breech mechanism and pepperpot muzzle brake that reduces recoil forces by 25 per cent
- The interior of the IWS ordnance is chrome lined to give increased barrel life
- Has an automatic muzzle reference system for the mounted on a forged upstand on the barrel
- New APFSDS round – named the 'T-2 series'

- Penetrates 540 mm of Rolled Homogeneous Armor at a range of 2,000 meters (unknown angle)​

- Weighs 19kg, 1030mm long, 1,420m/s MV​

- W-Ni-Fe penetator, 3-segment sabot​

- Length-to-diameter ratio is 23:1​

- Penetrator mass ~40% greater than 'current 105mm APFSDS' rounds​

- '30 to 40% greater than that of current 105 mm APFSDS rounds' (Wikipedia)​

Here's an image of a Leopard 1 mounting the gun. The image and most of the information above are from http://www.army-guide.com/eng/product3633.html.

I would like some better information from more reputable sources, though, specifically on the penetration figures/ammunition details for the T-2 APFSDS.
If anyone has anything, it would be greatly appreciated!

 

[kqcke for you]

I had searched for the same thing and fund some stuff to it but i have to search for it If i still have it.

 

[kqcke for you]

Here is a small part about it. For more i have to search as i think i deleted it

RO2004 Light Tank - Tank Encyclopedia

The RO2004 was the planned light tank variant of the RO2000 universal platform, armed with a 105mm gun. Only one vehicle was partially built.

tanks-encyclopedia.com

 

[kqcke for you]

Some more pictures

 

[ChieftainWarrior]

Some more pictures

These are amazing, thank you very much!

Do you know what mantlet this might be from, or is it just a generic one made for showcase?

 

[kqcke for you]

These are amazing, thank you very much!
View attachment 710089
Do you know what mantlet this might be from, or is it just a generic one made for showcase?

No i don't know but i think its either a generic, the one IT was proposed for at that time or the last on IT was on.

 

[ChieftainWarrior]

With the photos provided by @kqcke for you I calculated the following for the T-2 APFSDS using some ratios:
Penetrator length: 437mm
Frustum length: 37.75mm
Frustum diameter: ~2-3mm

I'm sure they're off by a couple mm at least, especially considering how pixelated the picture of the round without the canister is, but they're close enough.
I want to run a penetration calculation on it but I'm missing the density, I have everything else though.

 

[kqcke for you]

Well as far as i heard its some 540mm at 2km. So Take some density Numbers and try until you get this. But the big thing is that the design of the penetrator, Material compostion and "extern variables" can change how mutch "Penetration" it has. Same for modern armor which makes it a little ironic. You don't shoot against only rha but take the value you get from it as importend.

This is not directed at you Chieftain but more an observation as many want to know it me included as its the only value we ever get.

 

[ChieftainWarrior]

But the big thing is that the design of the penetrator, Material compostion and "extern variables" can change how mutch "Penetration" it has.

Oh, of course. I'm mostly doing it to just create some figures – I'd like to create some 'accurate' data for here but I'm aware in real life it would perform differently against different armour and whatnot.

Well as far as i heard its some 540mm at 2km.

Yes, that's what I've seen as well. Only issue is what this number represents. Is it flat-pen at 0 degrees? If so, I'm not sure I can work out the density accordingly, as the calculator provides data for 60 degrees and there isn't a nice way of converting between 0 and 60 degrees.

But if it represents 540mm LOS at 60 degrees at 2km (>270mm at 60 degrees), I could. That might match with the claims it exceeds 'current' 105mm APFSDS and reaches 120mm APFSDS levels, as it exceeds most 105mm rounds – except maybe DM63, I haven't found concrete penetration data for that –, and also exceeds estimations for 120mm DM13 and DM23, at least according to the following:

If these values are somewhat accurate, and the 540mm is LOS at 60 degrees, then it comes close to CHARM 1 (L26A1) 120mm APFSDS in performance. Pretty impressive.

 

[kqcke for you]

Yeah a shame 105mm dont get so mutch Love. They could be mutch better even today with more modern Materials and construction.

 

[kqcke for you]

View attachment 710108

If i remember it right this one wasn't accurate but for the reason why i would have to look it Up.

 

[Voltzz]

From IDR 9/1991:

The design standard of the T2-series ammunition is not yet fixed. It is understood that various iterations of reduced-vulnerability and standard propellant types are under assessment, including DX drawn from RO’s high-temperature RDX-based propellant range. The round’s overall length is 1,030mm; and in place of a normal brass cartridge, which deforms at high pressures and can be difficult to extract, it uses a nitrocellulose kraft combustible casing with a conventional primer, plus a steel stub-case for obturation. (A revised semi-automatic gear for case extraction forms part of the IWS integration package.)
The projectile features a standard three-segment aluminium sabot to support the tungsten nickel iron penetrator, with a mass said to be more than 30 percent greater than penetrators in comparable 105mm long-rod KE energy ammunition, such as RO’s own H6/62. The latter has a length/diameter ratio of 20:1, whereas the T2-series is both thicker and longer (diameter 28mm, L/D around 23:1). In comparison, its muzzle velocity is down from 1,490m/s to 1,420m/s, but the introduction of low-drag steel fins keeps the velocity drop to a respectable 48m/s/km.

RO is coy about quantifying the performance of its new round, other than affirming that it exceeds the homogenous steel armour penetration capability (ie. 540mm at 2,000m) normally ascribed to in-service 120mm smoothbore ammunition, which typically has a muzzle energy of 9MJ. Against a modern Soviet-designed tank (T-64B/T-72M/T-80), whose composite armour is augmented by applique explosive armour, it is assessed that an IWS-armed tank might have to assume a firing position marginally (no more than 200m) closer than one firing standard US M829 120mm smoothbore ammunition, which has a depleted uranium penetrator. Though aimed at the 105mm market, the T2 penetrator evidently has significantly more momentum even than some long/thin 120mm KE penetrator designs, and its greater rigidity makes it easier for it to overcome the shear forces produced by some modern target arrays.