Canada's purchase of the Leopard 2 MBT

[vonGarvin]

Kev
The longer barrel means of course that you can have a longer burn time for the propellent.  The point of "all burnt" can be microseconds longer than with an L44, which of course means higher muzzle velocity.  As well, any droop can be discounted by higher accuracy (due to fewer rounds being fired) (j/k on that one).  In all seriousness, the muzzle reference system (MRS) can offset droop, actually, compensate for it, I suppose would be more accurate.

 

[Ex-Dragoon]

Almost sounds like you are comparing it along the lines of a carbine to an assault rifle.

 

[McG]

Tanker or not, CF or not, your observations are far from irrelevant. 
though the Leo 2A6 is superior in one area: firepower.  Its gun is 1.3 meters longer than the earlier leos and M1A1+ tanks (which all have the Rheinmattel L44 gun).

However, the US KE rounds are fired with a much higher peak pressure in order to achieve the same kinetic energy at the muzzle.

 

[KevinB]

Almost sounds like you are comparing it along the lines of a carbine to an assault rifle.

Like I said before I was out of my lane and knew it -- so I went with a frame of refrence I knew
-- I was suprised they had not tried to find the optimun length prior - thats all.

 

[Ex-Dragoon]

No, you misunderstand me I6.....I was just musing outloud basically if the different barrel lengths would be comparable in performance to a carbine and assault rifle.

 

[KevinB]

Your the Ex-Armoured dude your supposed to know...

 

[vonGarvin]

Like I said before I was out of my lane and knew it -- so I went with a frame of refrence I knew
-- I was suprised they had not tried to find the optimun length prior - thats all.

Well, I think that there are alot of variables, some of which change as technology changes.  That Rheinmetall Gun was developed in the late 60's or early 70's, so machining was probably one thing that may have improved, as well as quality control ofthe gun, the muzzle reference systems (re: droop!) may not have been around, as well as increased propellent efficiency, etc.

However, the US KE rounds are fired with a much higher peak pressure in order to achieve the same kinetic energy at the muzzle.

Probably at a cost of Equivalent Full Charges per shot?  Just a guess...

 

[AmmoTech90]

We're also hitting a point of dimishing returns with regard to shot material and composition.  Once you get past a certain point with Mv it matters less and less if its DU or Tungsten and as you increase your L/D ratio you have to start considering segmented penetrators.
By increasing barrel length you get a longer burn time as Capt S pointed out.  This can help barrel life by being able to use cooler burning propellant but still generating the same pressure, or you can go for hotter propellant and have a longer push.

 

[ironduke57]

However, the US KE rounds are fired with a much higher peak pressure in order to achieve the same kinetic energy at the muzzle.

May I ask where you got that information from? AFAIK the US only changed the breach block and some minor thing´s for the there M256. The reason why there KE performance is on the same level as the DM53 fired from the L/55 is that they use DU for there APFSDS round´s.

Regards,
ironduke57

 

[Ex-Dragoon]

Been ex armoured for 13 years lol......Navy now

 

[KevinB]

Been ex armoured for 13 years lol......Navy now

Excuses, excuses...   

 

[Ex-Dragoon]

LOL I learned that in the Army

 

[Lance Wiebe]

May I ask where you got that information from? AFAIK the US only changed the breach block and some minor thing´s for the there M256. The reason why there KE performance is on the same level as the DM53 fired from the L/55 is that they use DU for there APFSDS round´s.

Regards,
ironduke57

I am also curious as to the source of this information.  AFAIK, the peak pressure of the US AFFSDS-DU M829A2 & A3 rounds is virtually identical to the DM53.  The DU round, however, provides near identical penetration as the DM53, due to the nature of the beast.

 

[McG]

May I ask where you got that information from?

Benet Labs.  I cannot seem to get to my source at the moment, but but this covers it:  http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA406817

AFAIK the US only changed the breach block and some minor thing´s for the there M256. The reason why there KE performance is on the same level as the DM53 fired from the L/55 is that they use DU for there APFSDS round´s.

It was not changes to the weapon so much as accpeting a re-assesment of the acceptable peak pressure.  Additionally, tighter tollerances are in place on barrel wear & manufacutre. 

 

[ironduke57]

Benet Labs.  I cannot seem to get to my source at the moment, but but this covers it:  http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA406817
It was not changes to the weapon so much as accpeting a re-assesment of the acceptable peak pressure.  Additionally, tighter tollerances are in place on barrel wear & manufacutre. 

Ah okay. Thanks. Do you have number´s how far the pressure was increased for the A3 and how much impact it has on it´s velocity?
I can´t think that the velocity was much raised with only the L/44 barrel. For example when fired from the L/55 the DM53/63 has an velocity of 1.750 m/s. But if it is fired from the L/44 it only has an velocity of 1.670 m/s. Not much more then the old DM33 with it´s 1.650 m/s. (Just for comparison. There is also the DM43. Developed in corporation with France. But we decide to wait for the DM53. The DM43 is only used by France in the Leclerc. It reach´s an velocity of 1.770 m/s. But I don´t know if this number is from firing it from an L/44, L/55 or the french L/52.) (I know that the velocity of the sabot isn´t everything but it is IMHO an relative good comparison base.

Also are the proportion of the sabot changed for the A3? (For example for the A1 I have a value of  24:1. For comparison the DM53/63 sabot has an value of 30:1.

Regards,
ironduke57

(I hope it is understandable what I mean. It is hard to talk about technical things in different languages.)

 

[Lance Wiebe]

Irondukes;

You do very well getting your point across in English!

Although this is open source, it does answer some questions. 

http://www.defense-update.com/products/digits/120ke.htm

It claims that the DM53 has a chamber pressure of 5,450 Bar.  It does not state the chamber pressure for the DM63 or the M829A3. 

I'm not sure that this site has all of the correct facts, although the M829A3 projectile weight would certainly increase chamber pressures by quite a margin if it indeed weighs 10 KG!  The weight would also account for the slower muzzle velocity.

 

[Lance Wiebe]

Holy crap!

It appears that the M829A3 has a chamber pressure of 7590 Bar!

According to this article, only new barrels can fire it.  Here's the link:

http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=A406817&Location=U2&doc=GetTRDoc.pdf

If that doesn't work, go here:

http://stinet.dtic.mil/ and search for M829E3.

 

[Lance Wiebe]

Darn.  Forgot to add that the M829A3 projectile is 924 mmlong, width of 25mm ( surprising, given that the M829A1 was 22mm!)

That would give it an L/D ratio of 37:1

 

[McG]

Ah okay. Thanks. Do you have number´s how far the pressure was increased for the A3 and how much impact it has on it´s velocity?

While my source is off the net, I’ve got nothing.  However, with all the numbers already turned up in this thread, I would be surprised if much more is available open source.  The US can’t possibly want an enemy to be able to calculate the penetration potential of its most lethal tank round.

 

[TCBF]

Velocities are generally available.

But: the actual mass of the projectile - in this case, the 'dart' - is normally unlisted.