S. Berliner, III's sbiii.com ORDNANCE 175mm Baby Atomic Cannnon Towed Mount Page keywords = 175mm baby atomic cannon T145 towed mount T76E1 ordnance Aberdeen Proving Ground history artillery gun rifle recoil Maryland shell cartidge casing Ft. Sill Oklahoma ammunition ammo round

Updated:  03 Nov 2016; 13:30 ET
[Page created 07 Dec 2012;

[original AT&T Worldnet Website begun 30 May 1996.]
URL:  http://sbiii.com/ord175tm.html

S. Berliner, III
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"changing materials with high-intensity sound"

[consultation is on a fee basis]

Technical and Historical Writer, Oral Historian
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note - The vast bulk of my massive Web presence (over 485 pages) had been hosted by AT&T's WorldNet service since 30 May 1996; they dropped WorldNet effective 31 Mar 2010 and I have been scrambling to transfer everything.  Everything's saved but all the links have to be changed, mostly by hand.  See my sbiii.com Transfer Page for any updates on this tedious process.

S. Berliner, III's


175mm "Baby" Atomic Cannon
Towed Mount Page


Please refer to the HELP section on Continuation Page 3.


On the main Ordnance page:

On Ordnance Continuation Page 1:
    (Moved from Ordnance Page 2 on 12 Feb 2002).
  More on the 280mm Atomic Cannon - moved to this page 26 Aug 03.

On Ordnance Continuation Page 2:
  ATOMIC CANNON - moved to this page 26 Aug 03.

On Ordnance Continuation Page 3:
  CALIBER (Calibre).
  Anzio Annie.
  SMALL ARMS (moved from Page 2 on 13 Apr 00)
  Russian Armor.

On Ordnance Continuation Page 4:
  Drake Gun/Cannon
  Coastal Defense Guns at Fort Casey
  M274 Mechanical Mule

On the Atomic Cannon Pictures Page:
  Atomic Cannon CQ (Seek You = HELP!)

On the Atomic Cannon Pictures Page:
  Battery B, 265th Field Artillery Battalion, Baumholder, Germany, 1955 and 1956.
  Atomic Cannon Training Manual.

On the Atomic Cannon Continuation Page 1:
  Atomic Cannon in Asia!

Atomic Cannon Pictures Page.

On this 175mm "Baby" Atomic Cannon Towed Mount Page.   rev (13 Dec 2012)
  175mm "Baby" Atomic Cannon Towed Mount
  Atomic Cannon Background.

On the Ordnance Railroad Guns Continuation Page:
    (continued from Ordnance Continuation Page 2)

Ordnance Models Page.

The Ordnance Supergun Page.

Comet Metal Products Authenticast Models Page.


As noted on Page 1, army ordnance buffs should visit the Ordnance Museum at Aberdeen Proving Ground off Routes 40 and I95 just south of Havre de Grâce and the Susquehanna River Toll Bridge - very much worth the time (and allow plenty of that, in proportion to your interest!).  There are acres of tanks and armored vehicles, domestic and foreign, of all eras, Anzio Annie, a 280mm Atomic Cannon, a 16" coastal defence gun, a V1 buzz bomb and a V2 rocket, and a great indoor museum with a fine small arms collection!  This fabulous museum is an absolute must for the ordnance devotée!  More about the Museum and its history is on Page 1.

    [Check first - the Museum is moving to Ft. Lee, Virginia!]

Here is Anzio Annie (the 280mm German "Leopold" K5 railroad gun before she came to APG:

Anzio Annie (Leopold)
(Ordnance Museum Foundation Photo)

Annie was the design basis for our 280mm Atomic Cannon.(Atomic Annie, et seq.)
and for the 175mm "Baby" Atomic Cannon towed mount with which this page is concerned.

[More on Anzio Annie on Page 3.]

175mm "Baby" Atomic Cannon Towed Mount (13 Dec 2012)

[Our own M-65 280mm Atomic Cannon was also a Schnabel vehicle; the T-131 cannon was mounted on a bridgework carried between two huge rubber-tired 6x6 truck tractors with load arms (the T-10 Heavy Artillery Transporter); the front truck has load arms pointed to the rear while the rear truck had the load arms pointed toward the front.  When they were deployed in Germany after the war (WWII), as the production M65, they tipped over with appalling regularity while traversing tight turns in tiny towns {a tongue-tripper}.]

However, a smaller version of the 280mm gun was developed, probably as a stop-gap measure until the later 155mm atomic round was available.  The Wikipedia article on atomic cannon shells documents development of the 280mm from the then-extant 240mm and then scaling down to 203mm (8") and finally 155mm, but does not mention the intermediate 175mm stage.

Nevertheless, the 175mm piece was most definitely intended as an atomic weapon; I tested it at Aberdeen Proving Ground ca. 1952-54.

A little background first:

The towed mount (I believe two were built) was quickly overshadowed by a self-propelled version with an enclosed cab based on the T97/M53 155mm Self-Propelled Gun and T108/M55 8" (203mm) Self-Propelled Howitzer. but with a wider hull, wider tracks (28"), and a heavier firing spade (among other things), the T162.  I also tested the T-162 at APG.

Enclosed cab SPs were intended primarily to provide protection against small arms, fragments, and radiation.  All three enclosed SPs were then dropped in the early 1960s in favor of more readily air-transportable open SP carriages, the 175mm gun M107 and the 8" howitzer M110.

An odd so-called "Atomic Annie" carriage and gun sits on display at the Air Power Park at 413 West Mercury Blvd. in Hampton, Virginia; it has strange bands around the barrel and I at first hoped it was "my" 175 but it's not; in spite of being wrongly identified all over the 'Net, it is actually the 240mm prototype of the 280.

The only remaining T162 enclosed 175mm gun (of three built) turned out to be on display at the Field Artillery Museum at Fort Sill, Oklahoma.

The Field Artillery Museum also turned up an "experimental 175mm gun and what are probably parts of its mount"!  I rather imagine it's the barrel from the towed mount.

[Pictures follow.]

PLEASE - if you know anything at all about "my" Baby Atomic Cannon, the 175mm Towed Mount, let me know; pictures would be greatly appreciated.  It looked just like the big M65 when set up on the ground for firing but had a fifth-wheel pin under the front end (I don't recall if it sat directly on a 5- or 10-ton 6x6 or on a two-wheel dolly and a removable (or retractable) one or two axle bogie under the rear.  Here's a rough image of how I recall it looking when set up for travel   rev (07 Dec 2012)

(07 Dec 2012 sketch by and © 2012 S. Berliner, III - all rights reserved)

[For ease of representation, I used an M26 12-ton Tractor (Dragon Wagon) to illustrate this possibility.]

I no sooner doctored up that image of a possible road configuration than I found this older sketch of a firing configuration.  One problem of memory is that I may have the bogie arrangement confused with those of the towed 40mm AA single Bofors, 75mm Skysweeper AA, 120mm AA, or 155mm gun/8" howitzer.

I'd made up a very crude image of what I recall the towed mount looked like in firing position:

(Ca. 15 May 2012 sketch by and © 2012 S. Berliner, III - all rights reserved)

Thinking about it, I have a feeling that there was a towed bogie under the front (breech) end; more like this sketch (sticking with the Dragon Wagon):

(25 Feb 2014 sketch by and © 2014 S. Berliner, III - all rights reserved)

Someone, somewhere, besides me, must know about that gun (the museums don't, although, as I noted, Ft. Sill may have the barrel)!

HA! - Someone, somewhere sure does!  The archivist at Ft. Sill dug up this image, P13158, which clearly shows the mount I remember:   new (23 Apr 2014)

(10 May 2012 image courtesy of Field Artillery Museum, Ft. Sill, OK - all rights reserved)

To save you some trouble, here's the image alone, with a modified T145 175mm gun on the T76E1 towed carriage:   rev (22 Jul 2014)

(enlarged 10 May 2012 image courtesy of Field Artillery Museum, Ft. Sill, OK - all rights reserved)

Here's the text:

(text from 10 May 2012 image courtesy of Field Artillery Museum, Ft. Sill, OK - all rights reserved)

And, here's the T76E1 carriage alone:   rev (22 Jul 2014)

(enlarged 10 May 2012 photo courtesy of Field Artillery Museum, Ft. Sill, OK - all rights reserved)

That means that my original recollection of a retractable, single-axle, trailing bogie was right all along, so the sketches should look like these:

Towed175mmBabyAtomicCannon2 TowedBogie175mmBabyAtomicCannon
(23 Apr 2014 sketches by and © 2014 S. Berliner, III - all rights reserved)

Here's the T145 gun tube on the ground at Ft. Sill (left), with the breech carrier and two breech blocks and the obturator and obturator pad at the bottom (center), and the two breech blocks and carrier up close (right):   rev (22 Jul 2014)

Towed175mmT76E1Tube1 Towed175mmT76E1Tube2 Towed175mmT76E1Tube3
(ca. 10 May 2012 photos courtesy of Field Artillery Museum, Ft. Sill, OK - all rights reserved)
[Click on thumbnailed images for MUCH larger pictures]

Towed 175mm T145 Gun Components   rev (22 Jul 2014)

I'd guess the smaller block is from a 155mm gun.

From Wikipedia's article on Gerald Bull:

"In early 1963 HARP started experimenting with the Martlet-3, a 7-inch-diameter (177.8 mm) "full bore" projectile designed to test the basic problems of launching a solid-fuel artillery shell from guns.  Solid shell fuel has the consistency of soft rubber and is cut into a pattern that is open in the middle, so on firing the 'grain' would tend to collapse into the cavity.  This problem was solved by filling the cavity with zinc bromide, a liquid that had a density close to the fuel which prevented the collapse and was then drained out after firing to allow the shell to light.  Test firings began at the US Ballistic Research Laboratory in Aberdeen using a bored-out 175 mm gun from the M107.  This program proved the basic concept and shots of the Martlet-3 reached altitudes of 155 miles (249 km)."

Sure sounds to me like that T145 175mm gun tube at Ft. Sill is from the T76E1 towed mount, NOT one from an M107 (the much-later open-cab SPG)!   rev (22 Jul 2014)

That P13158 image is very definitely of the mount I was trying to locate and the tube is reinforced/braced exactly like the HARP guns.  That almost certainly would be the tube smooth-bored out to 7" and firing at such an extreme angle (now just how did they manage to achieve such high elevation? - max. elev. probably matched the 280mm's 55° / 978mils) could have easily wrecked the carriage.

Further, I very much doubt the "ca. 1945" dating; ca. 1964 is much more likely.  That test almost certainly occurred AFTER my testing the towed 175mm at APG ca. 1952-54.  Per Ft. Sill: "In 1950, the U.S. Army Equipment Development Committee recommended a gun of about 170 mm be developed to replace the 155 mm M2 'Long Tom'", thus making 1945 quite out of the question.

Now we're getting someplace, indeed!  My deepest apologies to the crew at Ft. Sill for not posting all this latest information sooner.

Whil(e)(st) correcting a whole slew of T-number typos/transpositions above (22 Jul 2014), I realized that the gun tube on the ground is highly unlikely to be the one returned from the HARP project.  The HARP gun was bored out, lengthened considerably, and heavily braced; the tube on the ground is normal length and unencumbered with any external modifications.  I'll bet it's a perfectly ordinary T145 (as if there was any such thing!).  If it's rifled, it's definitely a "normal" barrel.   new (22 Jul 2014)

Also, "in a firing pit of Ballistics Research Laboratories at Aberdeen"?  I don't recall any such firing positions at APG; BRL used our regular APG facilities and personnel for their heavy, outdoors firing tests.  This discrepancy bothered me enough to look up an old buddy and fellow former Ordnance Proof Director who confirmed just that.   added (22 Jul 2014)

Weird - there's now (22 Jul 2014) an on-line listing for "175mm Gun Carriage, T76E1: Notes on Development Type Materiel" by Franklin Institute, Laboratories for Research and Development, Philadelphia, Pa., 1953, 1953 - 39 pages, OCLC Number: 56667406, but no way to obtain it!  The Field Artillery School at Ft. Sill, Oklahoma, has the only listed copy - I'll have to look into this further.   new (22 Jul 2014) and rev (03 Nov 2016)

I had intended to carry this further with text and pix of the M-107 175mm Self-Propelled Gun, the open mount, used so extensively in Vietnam and in Israel; bear with me, please.   new (03 Nov 2016)

The ORDNANCE Main Page had to be split; it continues on ORDNANCE Continuation Page 1, et seq.


  What happens to all this when I DIE or (heaven forfend!) lose interest?  See LEGACY.


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