Armour penetration and repeated hits.

[kipanderson]

roqf77,

I agree that the L30 gun does all the tricks, but the reason for the likely move to a version of the L55 gun is to make it compatible with everyone else’s 120mm ammo. Whether we produce some ammo types, and then buy in some other types, there will be huge savings due to far greater production runs if all can use everyone else’s ammo.

The MOD believe that the re-gunning of Challenger 2s with the L55 will save money over the life of the guns. The savings in ammo would be so great. The motivation is financial. Get an equally capable gun, for less over its life time costs.

All the best,

Kip.

[John D Salt]

Originally posted by kipanderson:

[snips]

The MOD believe that the re-gunning of Challenger 2s with the L55 will save money over the life of the guns. The savings in ammo would be so great. The motivation is financial. Get an equally capable gun, for less over its life time costs.

A terrible shame to lose the HESH capability, though. Whatever wars we will be fighting in future, I expect that a lot of rounds will be expended against concrete, brick and adobe, and HESH is clearly a much better bet than HEAT for this.

I know that donkey-wallopers of the Fuller/Liddel-Hart/Tal school hate the idea of armour acting in support of infantry, but it really is an important part of its job.

All the best,

John.

[roqf77]

kip this is true. this is why i ask, i just put it badly.

The new round being developed by the mod is for the new 120mm gun not the current one. is it the same round as all the others or is it our own one so to speak.

[roqf77]

and i agree with jon it is also my understanding that hesh is better than heat.

[flamingknives]

Originally posted by roqf77:

i am aware of that. i was just wondering about the ammo. as the uk is developing a du round with a larger round and longer. still 120mm but as its sabot the dart is being increased. i was just wondering if they were related in any way.

The L30 cannon on the Challenger is a totally different gun to any of the smoothbores, especially the 120mmL44. For a start the L30 is over 50 calibres long.

Then you've got the ammo thing. You cannot fire a round designed for a rifled gun out of a smoothbore, or vice versa. Well, you could, but it wouldn't be a terribly good idea.

Both the L30 and the smoothbores fire APFSDS rounds. The rifled L30 uses a slipping driving band on the sabot to reduce the spin to minimal rates. In fact, having a slow spin on an APFSDS round is good, as it has almost no effect on penetration, but smoothes out the aerodynamic effect of manufacturing flaws. APFSDS fired from smoothbores, AIUI, have slightly canted fins, whereas APFSDS from rifled guns retain the residual spin.

The Challenger Lethality Improvement Programme (CLIP), being conducted by BAESystems Land Systems, involves fitting a 120mmL55 smoothbore cannon to a Challenger 2 turret. AFAIK, the only modifications are to make the external dimensions of the gun match that of the L30.

Agree with John about the HESH. It seems to be a great secondary round.

[roqf77]

true but what about the round? ive double checked. the project to produce a sabot round with a larger and longer du dart is still happening. So i take it this round s for the new smoothbore gun.

[c3k]

Gents,

My ignorance is showing here: please help those of us trying to follow by defining the weapons being discussed. What are the bore diameters/barrel lengths and other distinguishing characteristics of the L30/L44/L55 cannon?

Thank you.

Ken

[kipanderson]

John,

“I know that donkey-wallopers of the Fuller/Liddel-Hart/Tal school hate the idea of armour acting in support of infantry, but it really is an important part of its job.”

I too agree with your views on Mesh and the us eof tanks.

It I interesting that if one reads the MODs own after action report on Gulf War 2 they also make clear that heavy armour is a useful today as it has ever been. So do the US after action reports.

Combines arms, including armour with big guns, is still the way to go. Armoured cars running around with stand-off missiles has its place, but not as a replacement for tanks .

All the best,

Kip.

[roqf77]

wait for flaming knives to give a better answer.

but for now. the l30 is the cannon on the challenger 2. it is 120mm(they all are), it has a rifled barrel with cromium lining to reduce wear and increase velocity and therefore penetration as fn pointed out it barrel length is over 50 calibres.

the confusion arises because the british dont use standard designation for barrel length. the l44 and 55 are both rheinmetal guns(120mm too).

L44 and 55 refers to the length in calibre of the gun. so the l55 has a longer barrel the muzzle vewlocity and energy is higher therefore giving higher penetration.

all guns fire apdsfs rounds. the british gun has the secondary round of high exsplosive squashed heads and the others high exsplosive anti tank.

From my understanding the hesh round is somewhat better than the heat.(both dual purpose but primarily anti infantry/building weapon etc)

[Kurtz]

Originally posted by c3k:

My ignorance is showing here: please help those of us trying to follow by defining the weapons being discussed. What are the bore diameters/barrel lengths and other distinguishing characteristics of the L30/L44/L55 cannon?

The L30 is obviously something else, but the L44 and L55 is a description of the length of the barrel measured in calibers.

E.g.

L44: 44 times the caliber (120 mm) = 5280 mm = 5,28 m

L55: 55 x 120 mm = 6600 mm = 6,6 m barrel lenght

It the caliber was smaller, the results would differ. The barrel of a 105 mm L44 gun would be 4620 mm long.

[flamingknives]

Originally posted by c3k:

Gents,

My ignorance is showing here: please help those of us trying to follow by defining the weapons being discussed. What are the bore diameters/barrel lengths and other distinguishing characteristics of the L30/L44/L55 cannon?

Thank you.

Ken

Designed/built by Rheinmetall

120mmL44:

120mm smoothbore

44 calibre barrel length (5.28m)

Used on the Leopard 2 up to the 2A5 model. A derivative is used by the M1A1 and later Abrams.

120mmL55:

120mm smoothbore

55 calibre barrel length (6.6m)

Used on the Leopard 2A6 and being trialled for the Challenger

Designed/Built by Royal Ordnance (Now part of BAEsystems Land Systems)

120mm gun (L30) Note: L30 is the designation, not barrel length

120mm rifled gun

55? Calibre barrel length (6.6m)

[roqf77]

sorry my mistake. the charm 3 round with the larger and longer dart is currently in service in the uk.

[Kurtz]

It may look like an easy solution to just add a longer barrel, but imagine trying to drive through the woods or turning a corner in a city with a 10 meter long barrel! :eek:

The Swedish Leopard 2 (L44 gun) only have APFSDS and HE (converted 120 mm mortar projectiles), no HEAT or HESH. The HE round is considered effective enough to use against light armoured vehicles.

[ September 05, 2005, 12:49 PM: Message edited by: Kurtz ]

[c3k]

Gents,

Well done! Thank you. I'm very familiar with 120/L44. I was unaware of the longer variant, L55, as well as the talk about non-backward compatible rounds. Whereas I knew the Challenger used a rifled 120mm cannon, I did not know its designation. (Why, in the name of all that's holy in ordnance, did the MOD use the "L30" nomenclature?)

Finally, earlier there was some talk about using a "140" cannon. Or was it "(small)L" "40"?

Thanks,

Ken

[Kurtz]

Leopard 2 with prototype 140 mm gun:

More kinetic energy but less rounds in the vehicle. And as I mentioned above: a challenge to drive in woods and towns. Right now the 120 mm gun is sufficient to kill the likely targets, so don't expect to see it in production anytime soon.

[roqf77]

140mm cannon. there are ones currently in development by most nations. but i dont realy know the details.

[flamingknives]

Why did the MoD use the L30 nomenclature?

One might ask why ze Germans use L## to describe guns, rather than a sensible designation number.

L## is standard MoD Description number for weaponry.

Some examples:

L1A1 = SLR (FN FAL based rifle)

L85 = the current SA80 rifle

L86 = the associated light support weapon

L110 = the recently acquired Minimi light machine gun.

[Kurtz]

At least Britain have abandoned the pounder system.

[roqf77]

nothing wrong with the pounder system lol.

[Sequoia]

Originally posted by YankeeDog:

In re: crew losses.

'twould be great to see modeling of who, exactly gets hit.

Another element that needs to be considered is the internal design of the specific AFV, and how quickly and easily one crew member can take over another's job.

The Stuart, for example, has redundant drive controls for the Radio Operator, so he can take over driving the tank very quickly if just the driver gets hit. I'm not sure, but I think the T-34 may have had this arrangement as well. On the other side of the spectrum, in some tanks it is not possible to get from the turret to the forward compartment where the driver (& radio op/bow MG/whatever, if the tank has one) sat without going outside the tank.

Cheers,

YD

I'm bumping this thread not to restart the debate on the relative merits of modern tanks but in hopes of enlisting discussion of YankeeDogs comments posted here.

[c3k]

Ditto:

I've petitioned... Well, whined a lot anyway about including internal systems in the penetration model. Include kinematics and resistance of various systems.

Example: Shell penetrates turret side and has 100 units of energy left after penetration. That turret side had the tank radio mounted there. It is destroyed with 10 units of energy. The shell has 90 units left. Continue tracking the shell until it exits the vehicle or is unable to create further damage. The vehicle, if it survives with crew, will lose any systems damaged/destroyed by the shell.

Ken

[Ardem]

I am curious, people continue to say rounds exit the vehicle, i think with light armour this can be correct in straight through shots, but with medium armoured vehicles how regular was it for shells to enter and ext a vehicle.

[roqf77]

how long is a piece of string lol. ive seen pictures of shermans holed by 88mm pak 43's. that put holes through both sides. i suppose a 17 pounder hit through the sides of a panther may be able to go through both sides.

[Michael Emrys]

Originally posted by Ardem:

...with medium armoured vehicles how regular was it for shells to enter and ext a vehicle.

Not often at all, but it did happen now and then and has been recorded. People tend to glom onto that factoid because of the "Wow!" factor, and want to see it happen a lot.

Michael

[c3k]

Gents,

Well, straight-through penetration seems to be easily modeled. (This is where the various penetration grogs will jump all over me. )

Slopes, hardnesses, thicknesses, etc., are all known. How much shell deformation occurs after the initial penetration would be the biggest unknown factor. Residual velocity, hence energy, could be calculated. Reduce it for going through such things as sights, radios, the gunner, etc., and you'll have the velocity with which it strikes the inner face of the opposite armor.

Ken