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Subject: 120mm AMS in Australian service
BLUIE006    6/2/2008 4:45:13 AM
The 120 AMS (120mm Armored Mortar System) is a single barrel, smoothbore 120mm mortar turret suitable for integration on medium weight armored vehicles such as M113 and Piranha III. It is operated completely under armor featuring reduced recoil and semi-automatic loading system which makes possible integration on most types of wheeled and tracked vehicles. The 120 Armored Mortar System mortar-turret fires existing and planned 120mm mortar ammunition and can be employed for direct fire engagements as well as indirect fire engagements. A 7.62mm machine gun and smoke grenade launchers provide additional self-defense capability. h*tp://www.deagel.com/Weapon-Stations/120-AMS_a001428001.aspx The 120 AMS has been integrated on M113A4 and Piranha III 8x8 chassis and is currently in service with the armies of Saudi Arabia and Australia. Australia / 20 Saudi Arabia / 73 I had no idea ADF used 120 mortar?? Is this part of MINCS(L) AMP 48.36 – Army Mortar System Project The DMO site says its unapproved
 
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Herald12345    Why can't you do this everywhere you post?   6/14/2008 5:22:47 PM

A certain amount of dodgy info here.

 

Max rg unassisted for L118 is indeed 17.2 km with Ch S. There is an assisted BB shell giving 20km on paper but report from UK shoots in hot and high conditions (trials) suggest closer to 22 km, however, the dispersion is probably horrible.

 

That said Ch 5 still gives 15 km.  IIRC Ch S is 1 EFC and the barrel life is normally quoted as 10,000 EFC.  UK also holds slightly over 1 spare barrel per gun, this is not a big deal.  That said 52 cal 155 barrels are supposed to be good for 2500 EFCs but there are reports that it's a heap less, they're also very expensive, which is almost certainly why UK abandoned their 52 cal program for AS90 when it turned out the S African low wear propelling charges wouldn't meet insensitive ammo standards. When you think about this 52 cal may not be such a smart idea, it depends on what ammo is used in training and its EFC value, but on ops it could be real nasty.

 

The other point about L118 is its new ammo, not just the L51 Red Phos smk but the L50 HE with PBX fill and meeting insensitive ammo standards.  BAE claims (and it obviously means the best target type for comparison) that L50 has the same lethality as 155mm M107.  UK is currently upgrading their L118s including replacing steel platform and rock spades with titanium ones to reduce weight.  They also plan to keep it in service until 2023, but a 50th anniversary in service in 2025 seems likely!

 

As I understand it Aust originally purchased 15,000 rds 105mm Fd Mk2 (which is what L118 uses) and the plan was for local production.  However, this never eventuated for reasons that aren't at all clear but still seems to rile some people.

This I understand, since it is right up the old data alley. I actually learned something NEW from you [surprise!], so my day is not wasted.

Herald
 
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gf0012-aust       6/14/2008 11:36:23 PM

the plan was for local production.  However, this never eventuated for reasons that aren't at all clear but still seems to rile some people.
Definitely not precise recall from me, but IIRC it was a political decision focussed on minimising expenditures...  plus there might have been some political push to trade off against other ammo sellers such as the sth koreans...

 
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ArtyEngineer       6/15/2008 12:59:31 AM

A certain amount of dodgy info here.

 

Max rg unassisted for L118 is indeed 17.2 km with Ch S. There is an assisted BB shell giving 20km on paper but report from UK shoots in hot and high conditions (trials) suggest closer to 22 km, however, the dispersion is probably horrible.

 

That said Ch 5 still gives 15 km.  IIRC Ch S is 1 EFC and the barrel life is normally quoted as 10,000 EFC.  UK also holds slightly over 1 spare barrel per gun, this is not a big deal.  That said 52 cal 155 barrels are supposed to be good for 2500 EFCs but there are reports that it's a heap less, they're also very expensive, which is almost certainly why UK abandoned their 52 cal program for AS90 when it turned out the S African low wear propelling charges wouldn't meet insensitive ammo standards. When you think about this 52 cal may not be such a smart idea, it depends on what ammo is used in training and its EFC value, but on ops it could be real nasty.

 

The other point about L118 is its new ammo, not just the L51 Red Phos smk but the L50 HE with PBX fill and meeting insensitive ammo standards.  BAE claims (and it obviously means the best target type for comparison) that L50 has the same lethality as 155mm M107.  UK is currently upgrading their L118s including replacing steel platform and rock spades with titanium ones to reduce weight.  They also plan to keep it in service until 2023, but a 50th anniversary in service in 2025 seems likely!

 

As I understand it Aust originally purchased 15,000 rds 105mm Fd Mk2 (which is what L118 uses) and the plan was for local production.  However, this never eventuated for reasons that aren't at all clear but still seems to rile some people.

Regarding highlighted, 
That 2500 EFC is a valid number or therabouts for most 155mm tubes, however its important to note that that number is a "Fatigue" value for the life of the tube.  The primary criteria for condemnation of tubes is wear, if you are shooting the current top charges you are going to hit wear condemnation criteria a long time before you have fatigued your tube. 
 
Regards
 
Arty

 
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neutralizer       6/15/2008 2:13:07 AM
Wouldn't disagree with that, I've never come across a artillery barrel being condemned for fatigue.  Since 52 cal has more powerful max charge than used with 39 cal  this means that its max charge should have a higher EFC value.  Therefore hoping to get the same barrel wear life as a 39 cal barrel seems a bit optimistic.  Of course this makes assumptions about the nature of the propellant, particularly its burning temp, eg are modular charges basically single base or triple base?
 
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neutralizer       6/15/2008 2:23:53 AM



the plan was for local production.  However, this never eventuated for reasons that aren't at all clear but still seems to rile some people.

Definitely not precise recall from me, but IIRC it was a political decision focussed on minimising expenditures...  plus there might have been some political push to trade off against other ammo sellers such as the sth koreans...



I too suspect cost saving.  I can just imagine an underinformed bean counter saying 105mm is 105mm we already make it we don't need the cost of a new production line.  Perhaps it was the propellant, as I understand it triple base needs completely different facilities to single base. 
 
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Aussie Diggermark 2    re: Neutralizers question   6/15/2008 8:13:12 AM
I am no artillery man, but as I understand it, ADF bought the "L118" barrels and Abbot ammunition in case of war. We use the L119 configuration and the old (but cheap and plentiful, if rather limited in range) 105mm ammunition that we used on our earlier M2A2/L7 guns for all peacetime training activities. An American type, from what I understand, but as I said, I'm no artillery man.

Anyway as we have never taken the guns on an operational deployment the barrels are still in their delivery packing...

I have it on good authority from 2 different sources that at least 4 Field and 1 Field are actually equipped with the longer barrels, but simply don't use them on cost grounds.



 
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doggtag       6/15/2008 9:27:30 AM

Wouldn't disagree with that, I've never come across a artillery barrel being condemned for fatigue.  Since 52 cal has more powerful max charge than used with 39 cal  this means that its max charge should have a higher EFC value.  Therefore hoping to get the same barrel wear life as a 39 cal barrel seems a bit optimistic.  Of course this makes assumptions about the nature of the propellant, particularly its burning temp, eg are modular charges basically single base or triple base?



But doesn't some of that have to do with the actual manufacturing techniques used in the barrel?
 
Build a 52-cal tube with modern metallurgy,
and compare that to a 39-cal tube built with 1950s or 1960s era metallurgy knowledge,
and I'd still be willing to bet that the newer gun tube,
even with higher pressures and temperatures,
will last longer.
Plus, as was mentioned, consider the chemistry of modern propellants as compared to powder charges designed a few decades ago (or more).
 
And perhaps even different modern alloys (even plastics?) allowing for softer driving bands and seals around a shell that don't wear out the gun tube as fast, either...?
 
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Aussiegunneragain    AD   6/16/2008 7:54:12 AM

I am no artillery man, but as I understand it, ADF bought the "L118" barrels and Abbot ammunition in case of war. We use the L119 configuration and the old (but cheap and plentiful, if rather limited in range) 105mm ammunition that we used on our earlier M2A2/L7 guns for all peacetime training activities. An American type, from what I understand, but as I said, I'm no artillery man.

Anyway as we have never taken the guns on an operational deployment the barrels are still in their delivery packing...

I have it on good authority from 2 different sources that at least 4 Field and 1 Field are actually equipped with the longer barrels, but simply don't use them on cost grounds.

As I said before, yes, we definately did have the L-118 barrels in storage in the gun sheds at Enoggera. However, they have apparently been fitted and fired from time to time to familiarise the gunners with the ammo system, which is quite different to use compared to the L-119 (the former doesn't use a cartridge and you ram the charge bags home, vs a cartridged based system for the latter.  They also used to have one with an L-118 barrel set up at the School of Artillery. We never used the L-118's while I was in service though.

 
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Aussiegunneragain    Neutralizer   6/16/2008 8:15:32 AM

A certain amount of dodgy info here.

 Max rg unassisted for L118 is indeed 17.2 km with Ch S. There is an assisted BB shell giving 20km on paper but report from UK shoots in hot and high conditions (trials) suggest closer to 22 km, however, the dispersion is probably horrible.

 That said Ch 5 still gives 15 km.  IIRC Ch S is 1 EFC and the barrel life is normally quoted as 10,000 EFC.  UK also holds slightly over 1 spare barrel per gun, this is not a big deal.  That said 52 cal 155 barrels are supposed to be good for 2500 EFCs but there are reports that it's a heap less, they're also very expensive, which is almost certainly why UK abandoned their 52 cal program for AS90 when it turned out the S African low wear propelling charges wouldn't meet insensitive ammo standards. When you think about this 52 cal may not be such a smart idea, it depends on what ammo is used in training and its EFC value, but on ops it could be real nasty.

The other point about L118 is its new ammo, not just the L51 Red Phos smk but the L50 HE with PBX fill and meeting insensitive ammo standards.  BAE claims (and it obviously means the best target type for comparison) that L50 has the same lethality as 155mm M107.  UK is currently upgrading their L118s including replacing steel platform and rock spades with titanium ones to reduce weight.  They also plan to keep it in service until 2023, but a 50th anniversary in service in 2025 seems likely!

 As I understand it Aust originally purchased 15,000 rds 105mm Fd Mk2 (which is what L118 uses) and the plan was for local production.  However, this never eventuated for reasons that aren't at all clear but still seems to rile some people.


I don't know which information you are calling "dodgy", but if it relates to what I said what I was getting at is that (to my understanding) there are no PGM's available for the Light Gun like there are for 120mm mortars or 155mm guns. The improvements to the type will allow it to undertake current missions better, but unless Australia want's to develop its own PGM's the type is strickly stuck on an evolutionary rather than a revolutionary development path.
 
If that's all the Pom's want to achieve then upgrading the Light Gun is probably the cheapest way to do it. However, I can certainly see the benefit in having a 30km+ PGM capable M-777 155mm battery supporting every Austrialian Army battalion. The potential to support troops at extreme ranges and to reduce ammo usage due to increased accuracy would be well worth the investment, IMHO.
 
Regarding base bleed ammo for the 105mm, my understanding is that it has been tested but not adopted by the British Army. I don't know whether it was to do with cost or problems with the ammo, but that is what I have read recently anyway. Happy to hear any updates on it though.
 
Finally, what I was always told about why we didn't licence produce L-118 ammo is that the Pom's either wouldn't give us a production licence or at least not on sufficiently favourable terms to justify it. It would make sense.... why would they give up monopoly production rights to that ammo system? Anyway, the L-20 ammo system for the L-119 has served us well enough for training, so it isn't a big drama. I believe the US has come up with some good upgrades for that barrel to, including a 19km capable RAP.
 
 
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neutralizer       6/17/2008 7:16:48 AM
As I understand it the last 105mm Fd Mk2 was expended about 5 yrs ago (give or take) by 23 Fd Regt, and as I said there was only 15,000 rds procured.  If DoD wanted to produce ammo they could have done, an article in Cannonball last year by the former project manager for Hamel made it quite clear that local ammo production was always the plan but couldn't explain why it was dropped.  The stuff about the UK IP owner being difficult is nonsense, they'd have done a deal, but like any manufacture of relatively modern ammo there would have been royalties (105mm tank ammo production licensed from the same source?).  Of course the royalties might have been greater if Aust had exported it, IP owners get funny over things like that.  It's called capitalism, even if the Peoples' Republic of Pucka don't like it ;-)
 
Technically, the 1935 pattern ammo (as the Light Gun General Staff Requirement called it, AKA 105 mm How in official UK parlance or M1 type if you want) is semi-fixed while while 105mm Fd, like 25 pr, is separate loading which permits a larger chamber without having a larger cart case not to mention different carts for top charge using a slightly different propellant.  Semi-fixed has the advantage of faster loading, it's a matter of opinion whether or not this is worth the disadvantages.  Of course the other advantage of 105mm Fd is its greater lethality, and a whole heap more with the new shell.  And that's what its all about.
 
Whether or not PGM or semi-smart will be developed for 105mm Fd is unclear.  The real problem with all assisted ammo without any smarts is the dispersion, large, and clearly not suitable for danger close, which is popular at the moment.
 
155mm 52 cal barrels seem to be chromed as standard, and I think this has long been US practice with 39 cal but not neccesarily by other nations.  Chroming does increase barrel life but my understanding is that there is still a problem with 52 cal.  The only currently known way to reduce barrel wear and extend barrel life is to have cooler gas against the chamber and barrel wall.  This is what the S African charge design did and the results were fantastic, no need for expensive barrel chroming and very long life.  Problem was their failure to meet insensititive ammo regs.  As I said in a previous post, without knowing what propellant is used in modular charges it's difficult to assess the problem.  However, its usefull to remember that the US traditionally uses single base prop and this is a bit hotter burning (hence a bit higher rate of wear) than the triple base used by UK and Germany. 
 
As for M777, the interesting question is why did UK reject it (and Caesar) in their trials.  No doubt some will say budget pressures but if they were really wonderful the benefits would have outweighed this.  My theory is they've woken up to old truths, M777 has a crap rate of fire and neither of them were much good for fast and wide traversing, which is proving essential in Iraq and has probably jogged folk memories. 
 
 
 
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