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Mid 70s successor to the M 109 SPG

uk 75

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I was leafing through a mid-70s book on AFVs recently and found reference to a replacement for the M 109 howitzer called the XM 197 (I think) which must have got cancelled in the 70s in favour of the continued upgrading of the M 109.
I have looked at all the big books on the subject and can find no other mentions of this programme, much less any artwork or models. Does anyone out there know more?

UK 75
 

smurf

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Crow and Icks Encyclopedia of Tanks (published 1975) has (nothing else at all)
XM179 155mm howitzer on armoured M110 chassis

Fred Crismon's US Military tracked vehicles has only XM136, a lightweight 155mm gun elevating 0 to 75 deg.on a very low profile chassis 1966 24'2 x 9'4 x 6'high, wt 24600lbs net 265hp petrol engine
and
Howitzer Improvement Program of 1985 leading to M109E4-2; M109A3E2; M109A6
Basically upgraded cannon and NBC protection and diagnostics for trouble-shooting faults, in a turret taller at the back.
(he doesn't list XM179, not XM197)

Somewhere I have a list of US Army T and XM numbers, but at the moment it seems to have 'walked'.
 

uk 75

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I believe the vehicle is the XM 179 self propelled gun, as I found a reference to it in a German book on armoured vehicles from about 1975. Looking at some Library copies of Janes Weapons Systems from the period I confirmed the reference but could find no other details. It seems to have been cancelled between 1975 and 1980.
 

cador

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Hi,
i think XM-297 is the 155mm gun for the Crusader SPH (XM-2001)
 

Pioneer

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uk 75 said:
I believe the vehicle is the XM 179 self propelled gun, as I found a reference to it in a German book on armoured vehicles from about 1975. Looking at some Library copies of Janes Weapons Systems from the period I confirmed the reference but could find no other details. It seems to have been cancelled between 1975 and 1980.

Once again uk 75 you have me hook, line and sinker on this topic!
I too have read something about such a program, but for the life of me, I haven't been able to find anything! Sorry :'(

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Old_ROF

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Hi,

Found the following reference to the program in:-

RESTRUCTURED DEVELOPMENT TEST (DT II) OF HOWITZER, MEDIUM, TOWED 155-MM, XM198 (U)
TEST PLAN
BY J. S. WHITCRAFT
MAY 1975

1.1.1 (U) The 155-mm howitzer system development program which led to the XM198 towed howitzer (test item), the XM164, XM201, and XM203 propelling charges (test items), and the M549 rocket assisted projectile (test item) began in 1964 when the US Army Combat Developments Command developed requirements for a 30,000 meter range system. Initial efforts were directed toward the XM138, a lightweight, unarmored, self-propelled howitzer with increased range. In mid 1968, the XM138 program was terminated and its remaining resources were applied to a new, armored, self-propelled 155-mm howitzer, the XM179. A requirement for a new airmobile, 155-mm towed system, the XM198, was also stated at that time. Because of high development cost, unacceptable projected production unit cost, and questionable design complexity, the XM179 program was terminated by the Army in December 1969. It was then decided to concentrate development efforts on a simple, lightweight, towed howitzer with an extended range. A primary thrust of the requirements document was achievement of the best reliability, maintainability, and durability characteristics attainable within the. state-of-the-art.

http://www.dtic.mil/dtic/tr/fulltext/u2/a301713.pdf

Hope this helps
 

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Wow, I haven't had any luck finding pics / drawings of these XM136 & XM179 155mm Self-Propelled Howitzer Program :(

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Pioneer
 

Old_ROF

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There are references to, and pictures of, a mockup of the XM62 155mm Soft Recoil SP Howitzer (1962) and a test-rig for the XM138 155mm SP Howitzer (1966) in Hunnicutt's book on the Sheridan.

Although he mentions the XM179 project it was only to say it was cancelled and the M109 was developed incorporating the long tube (39cal) XM185 cannon originally intended for the XM179. No illustrations or pictures though.

This upgrade alleviated the blast pressure problems of the M109 created when using the higher performance M119 charge system from the existing short barreled cannon to get improved range performance.
 

TomS

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These are all pretty basic Google searches, so apologies if you've seen all this before.

There's a reference to research done on variable height torsion bar suspensions in reference to the XM179 in the footnote here. Sounds like a pretty fancy piece of equipment was envisaged if they were concerned about dynamically adjusting ride height to endure terrain clearance while moving.

There's also a photo listed in the collection of the Joint Munitions Command:
2008.7.354 – XM 179 Howitzer, SP, 155mm
With the number on hand, you might have an easier time getting a copy from the JMC Historian's office, which has some contact info here.

PS: There's some previous discussion on our forum here:

http://www.secretprojects.co.uk/forum/index.php/topic,5157.0/
 

uk 75

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Tom


Thanks for this. As I am in the UK not the US, not sure how easy it would be to apply for a copy of the pic.
Hunnicut did so much research for his book I am surprised he omitted this pic if it is easy to obtain.
 

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