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Artillery: Light And Accurate
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June 2, 2009: Two years ago, the U.S. Army received its first M777A1 lightweight 155mm howitzers. The M777s cost $1.9 million each and the U.S. has bought 800 of them so far, for use by the army and marines (who are getting 377 of them). The manufacturer, BAE, has also received a contract to refurbish 33 M777s that just returned from service in Afghanistan. This will cost $91,000 per howitzer. The British designed howitzer is also used by Canada and Britain. The army uses M777s in airborne and Stryker brigades. A five ton truck is used to tow the guns, but a special, 4.5 ton LWPM (Lightweight Prime Mover) is available to do that as well.

The five ton M777A1 is 40 percent lighter than the weapon it replaces, the M198. This is because the M777A1 makes extensive use of titanium, and new design techniques. It fires shells with a maximum range of 40 kilometers (using RAP, or rocket assisted projectile, ammo). A crew of five operates the gun, which can be ready to fire in under three minutes, and ready to move in under two minutes. The M777A1 is light enough to be moved (via a sling) by CH-53E and CH-47D helicopters. It's sustained rate of fire is two rounds a minute, with four rounds a minute for short periods.

What will really make this gun useful is the new GPS guided Excalibur shell, entered service two years ago. Otherwise, it fires unguided shells that land anywhere within a 200 meter circle. That's at 25 kilometers range. Accuracy gets worse at longer ranges. But not with the Excalibur shell, which falls within a ten meter circle (the middle of that circle being the "aim point") at any range. The Excalibur shell is essential, because ten 155mm shells (of any type, with their propellant and packaging) weigh about a ton. Ammo supply has always been a major problem with artillery, and Excalibur is the solution.

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Duubz       6/2/2009 7:58:12 AM
I've not read anything about Britain using the Excalibur shell.Does anyone know if it is in use with the British army or if they have shown any interest in using the shell?
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HIPAR       6/2/2009 10:29:05 AM
Excaliburs are very nice against point targets and add a new capability to the field artillery.  A problem with those rounds is the cost of using them in the traditional role of the field artillery; an area weapon.  What would a 30 round Excalibur barrage against advancing infantry cost?  Does the payload delivered by 30 Excalibur rounds have the same effects upon  that target as would 30 ICM cargo rounds?
---  CHAS
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HIPAR       6/2/2009 10:46:27 AM
What modifications to the original design were required for acceptance by US forces?
Back in the late 90s, I was testing a radar for Crusader at Yuma Proving Grounds. A 'light weight' gun in test stopped by my firing site.  My test director and the gun test director started a conversation and started laughing.  Evidently, the test gun broke.
They like to make a lot of noise and break things at Yuma.
---  CHAS
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Sty0pa       6/2/2009 1:11:05 PM

Excaliburs are very nice against point targets and add a new capability to the field artillery.  A problem with those rounds is the cost of using them in the traditional role of the field artillery; an area weapon.  What would a 30 round Excalibur barrage against advancing infantry cost?  Does the payload delivered by 30 Excalibur rounds have the same effects upon  that target as would 30 ICM cargo rounds?
---  CHAS

I would hope that there's some sense of mission-appropriate deployment.
Using artillery to take out a single bunker or position?  Excalibur.  Using artillery as an area-supression tool or harassment in the rear-assembly areas of a brigade?  Having a 200' CEP isn't a big deal so use the cheaper shells.
I'd guess that in most cases an Excalibur shell would be more useful, mainly because you can use fewer rounds to get the job done more quickly and reliably.  But there are plenty of applications where just tossing tons of explosives in an area is 'good enough'.
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Spiky       6/2/2009 3:20:56 PM
Titanium made artillery, nice, how much does one of these M777's cost?
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JFKY    Spiky   6/2/2009 3:42:38 PM
Read for comprehension the next time and your question answers itself....
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Spiky    JFKY   6/2/2009 11:44:00 PM
Ha! My bad. That is what happens when you read too fast. Caught it too late, had already posted.
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neutralizer       6/4/2009 8:09:18 AM
UK does not use M777 and almost certainly never will (they've publically stated that they will not be acquiring any new types of gun until the 2020s).  However, they have announced compatibility trials of Excaliber with AS90.
Obviously they won't be buying Block 1 shells, reliability of 85% isn't good enough.  However, the announcement that Block 2 shells will achieve 98% (the same as GMLRS) by adopting a new mini electro-mechanical gizmo from a UK company is a different matter.
The really interesting thing is that the US Army is going to equip 43 Bde Cbt Teams with 105mm, assuming the armd and mech bdes stay with Paladin how many M777 units does this leave?
A 2D course correcting fuze suitable for 105mm is now within reach, possible reducing CEP to about 13 metres at max range with HERA/HEBB, and a 105mm version of Excaliber also now seems like a runner in a few years time.  With all this 155mm for light forces doesn't make a lot of sense, although it seems that only the US Army and UK have woken up to this.  The US is also upgrading their M119 with electronic sights (UK completed this for all their's in 2002) but if its not clear if they are following the UK with other upgrades such as titanium platform and rock spade.  UK's new general purpose bde org organisation due for announcement in a few months looks like putting some 105mm into all bdes to support stabilisation operations, while retaining AS90 for major cbt ops.
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doggtag       6/4/2009 2:08:21 PM
For what it's worth, it looks (from my view) that in the US Army, the M777 is principally going to be a Stryker Brigade toy.
A good majority of units outside of SBCTs who still train with the M198 will certainly still soldier on with the M198,..that is, unless they find themselves the unfortunate lot to get "converted down" to 105mm in some of the Army's considerations for restructuring.
The 39-cal M198 can achieve the same ranges as the 39-cal M777, and the trip-7's lighter weight was always seen as one of its key sell points critical to the whole SBCT concept (which if it flies anywhere, will most likely be in C-5s and C-17s anyway, not via C-130 or routinely underslung from Chinooks).
Standard BCTs, however, who aren't required by role to travel "anywhere in the world in 96 hours" and don't really have as pressing a need for the M777's light weight, their current crop of M198s will suffice,
and at the trip-7's cost, the US Army could never fully afford to replace all the M198s on a 1-for-1 basis, anyway (again, some suggestive plans speculate that some 155-equipped units may down-convert to 105 artillery, maybe even become 120mm mortar units, so it wouldn't really require a full 1-for-1 with every M198 still in service (are these even still being made new?)).
Groups like the Chinook-reliant 10th Mountain will probably retain their 105s, if for the fact they can lift in more ammo (a necessity for extended operations) for the same weight of 155 shells and charges, but they also should receive M777s because of their heavy utilization of Chinooks and the desire for precision fire (Excalibur).
I even anticipate the 10th will receive HIMARS as well (if they haven't begun to already).
Although I expect the PGK program, and a number of other course-correction fuze technologies, to mature into production-ready systems sooner, I doubt we'll see a dedicated (purpose-built) Excalibur equivalent in 105mm within the next decade, and certainly not 5 years from now (still seems to be a toss-up in the USAF ranks as to whether develop a guided 105 round for AC-130s ($$$ if just for that platform), or step the gun caliber up to 120mm mortar class for use of those guided projectiles already under development at someone else's expense).
I don't know how frequently that US forces are called upon to use their 105mm howitzers to their maximum ranges (~17km?), but 120mm mortars may continue to take more precedence in US Army service (I don't know exactly how close to production PGMM really is, and at how fast the plan is to procure them; there's an older article here at Defense-Update.Com ),
as they (mortars) are much lighter in weight (more readily portable if they're not SP systems) and have shown to reach >13km in trials with extended-range ammo (even though the M395's suggested design is/was claimed to barely reach 8km), plus can pack a slightly larger payload, even if they do lack the direct-role capability that howitzers can offer.
Having browsed the ammunition files over at General Dynamics Ordnance and Tactical Systems (doing so because their Advanced Cannon Artillery Ammunition Program (ACA2P) was developed from their experience with
South Africa's Denel and their Igala ans Assegai ammunition families,
and has been M-designation type-classified by the US (and is suitable for M119s, M198s, and M777s), even if its use isn't widespread), the 105 does still have some quite useful life left in it.
Precision kits will only continue to make it more useful.
A nearer-term precision fire solution for 105mm artillery might be by finding a means to make a separate-loading LAHAT compatible with the systems: launching at lower velocities than an MBT main gun, it would be interesing to see if it may be possible to fire the munition to its 8km range, or perhaps farther seeing as we can fire it in a higher-angle ballistic trajectory that tank guns can't achieve...?
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neutralizer       6/6/2009 1:59:14 AM

From an article in the latest hardcopy edition of International Defence Review by Rupert Pengelley (who?s been a defence journalist for decades and served in the HAC so knows a bit about arty)

PGK-1 precision has been sufficiently encouraging for it to be adapted to 105mm arty applications in its current configuration.

Colonel Ole Knudson, PM Cbt Arty Systems speaking at Defence IQ Future Artillery 2009 in March, ?the service?s future order of battle will include as many as 43 infantry brigade combat teams, whose organic artillery fire support will be in 105mm calibre.?

?Lethality studies have demonstrated that the effectiveness of 105mm HE ammo increases dramatically if the CEP of these rounds can be reduced to 30 metres, the relative improvement at that distance being even greater for 105mm rounds than it is for 155mm.?

?the M913 105mm HERA has a 19.1 km range with top charge, this could be diminished by roughly 5-7% if fitted with a PGK fuze?

?Infantry battns are also seeking the introduction of  ?an organic, responsive, precision-fire capability and they don?t want to have to wait? said Col Knudson. An operational requirement statement has therefore been drafted for a 120mm mortar PGK with accuracy of 10m or less costing between US$3000 and 5000 per round.?

Also states that a development contract for PGK-2 will be placed in 2010, goal is 30m CEP and cost US$3000 ? 4000. PGK-1 fitted to 155mm HERA M549 achieves between 13 and 21 m CEP when fired up to 20.5 km range (2/3 max) in trial conditions. US Army hoping to acquire a 105mm PGM with ?Excalibur-like? performance (10 m CEP).

Note that UK 105mm HEBB reaches 20.3 km with the L118 gun, has not been adopted for service probably because dispersion is too great, it?s just waiting for a PGK.

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