King of the Wild Frontier

by Alex Wellerstein, published July 20th, 2012

Of all of the many silly names for nuclear weapons system that have been given, Davy Crockett has got to be one of the odder ones, in my view.1

The “Davy Crockett” was a nuclear weapons system using the smallest nuclear warhead (by weight and yield, but not diameter) that the United States ever produced. The sucker was little — in photos it looks like it is just about a yard long, barely over a foot high.

I’ve eaten meals larger than that nuke.

By nuclear standards, it was, as one colleague has put it, “a mere firecracker.” Only .01–.02 kilotons — just a baby! From a physics perspective, you’re talking about a warhead that weighed 51 lbs yet put out the explosive equivalent of 10 to 20 tons of TNT — in other words, a weapon which has the explosive output of roughly 780X what it would it would be if it were made of conventional explosives. The largest conventional (non-nuclear) bomb in the US arsenal is the MOAB, which has a blast yield of some 11 tons of TNT, according to Wikipedia. So this is a nuke that sits right at the threshold of the conventional/nuclear range, in terms of energy output. Except for, you know, the radiation, which is a big part of its selling point.

The last atmospheric (above ground) nuclear test series that the United States ever had — just before the Limited Test Ban Treaty took effect — was to test the Davy Crockett system. The aptly named “Little Feller” tests were held on July 7 and 17, 1962; Attorney General Robert Kennedy, among others, was present to observer the test. (Last Tuesday was the 50th anniversary of the second one.)

Man-portable nuclear weapons: as sensible as using alligators as water skis.

As for the name “Davy Crockett” itself, it’s not at all clear who named this thing, or exactly why. It’s almost surely done in the spirit of the 1955 Disney movie — the “king of the wild frontier,” who “killed him a b’ar when he only three” — as prior to that he was a much more obscure figure in popular culture. The name apparently goes back to the earliest days of the project, in 1958.2

Personally, I think naming a nuclear weapon after a guy who (probably) died defending the Alamo in an utterly avoidable last-stand battle is a little grim, but nobody asks me my opinion on this sort of thing. Did the French name any of their nukes after Dien Bien Phu?

The Davy Crockett nuclear projectile. The “dimple motors” apparently would tell you if the nuke’s internal power supply was still working. Bet you didn’t know nukes needed batteries, did you?

All right, enough jibber-jabber, let’s look at some images.

I have — after a few weeks of effort, I might add — managed to get the Library of Congress system to cough up Army Field Manual FM23-20, “Davy Crockett Weapons System in Infantry and Armor Units,” which has some great Davy Crockett photographs that I’d never seen before, as well as notes on how you’d go about trying to use this thing.

You might wonder why this took me so long to get, but that would only prove you don’t use the Library of Congress very much. It’s a great place to work but they have a ridiculously large number of “items not found on shelf.” Fortunately they also have some very helpful research librarians.

The LOC has somewhat slow scanners, and somewhat expensive photocopiers, so I’m not going to reproduce the report in full (at least at this time). But it’s a cool thing, and here are my favorite parts.

First, the Davy Crockett was really two different systems — a “light” gun (the M28) and a “heavy” gun (the M29). They used the same ammunition; the only difference was how far they could shoot the projectile and how large the cannon was. Both could be mounted onto jeeps.

The light system had a range of up to 2 kilometers, whereas the heavy system could go up to 4 kilometers. So that’s pretty close, but again, it’s a small detonation. In theory you could do this totally “safely,” but heaven help you if you’re talking about complicated engagements. I wouldn’t want to be out there on the tactical atomic battlefield on any side, frankly.

The advantage of having these on a jeep is that you could wheel it around pretty quickly, and you could store half a dozen of the warheads in the back. I mean, who hasn’t thought about doing this once or twice?

It’s hard to tell, but yes, there are six of them in there, on the left.

But the really gobsmacking aspect of the Davy Crockett is that it was man-portable. They had “port-a-packs” (their term!) that a little squad of soldiers could use to trudge these things around in the field.

Easy and convenient!

The big guy, in the middle, has the nuke. The little guy, second from the right, wonders why they couldn’t just use the jeep.

The instructions in the manual explain that you — the guy in charge — needed to “indoctrinate” your squad with a sense of “urgency” when they used the Davy Crockett, so they would always be running around as fast as possible. It also mandates that, “The search for nuclear targets is constant and vigorous.” Vigorous!

OK, so you’ve got your squad. They are feeling urgent. You march them out. Suddenly, you see a nuclear target! What next? First, unload your “port-a-packs,” and assemble your tripod.

Next, get the gun barrel into the tripod.

Next, you put the propellant in. The projectile has no means of launching itself — it’s more like a grenade than a missile. The way the gun works is that you put a huge tube of conventional propellant behind the projectile, and then a long “launching piston.” The piston is attached to the nuke. When the conventional propellant goes off, it sends the piston flying, which in turn transfers that force to the projectile.

Next, you basically assemble the other parts of the gun, get the nuke ready to go (you can choose to have it go off in ways optimized for a “low” or “high” burst height — I don’t know what functional difference there was, or how a simple switch could change it) and carefully fit the nuclear projectile onto the front. (Please don’t drop the nuke. And I think it may be redundant at this point to note that you are instructed not to smoke around the nuke. If you need assistance, please call your IKEA service representative.)

Before you put the nuke on though, you’ve got to set the “timer dial.” This is actually located on the bottom of the nuke itself. This was a tricky thing, of course — you could only set it to a maximum of 50 seconds, and you wanted it to go off above the target in question, at the right height. The warhead was fairly “dumb” — it wouldn’t detect when the right time to go off was, you had to figure that out yourself to a pretty high degree of precision.

The Davy Crockett egg timer. As with all nukes, “safe” is a relative term…

What if you messed up, and the nuke just slugged into the target? It wouldn’t, according the manual, detonate on contact. It would just break — a “functional failure” or “DUD.”

What then? Well, it explains, in such a contingency, the procedure is to wait 30 minutes, then verrrryyyy carreefully (my interpretation) go over to the maybe-dud nuclear warhead you just shot, recover it, and then pass it off to people who knew how to service nuclear weapons. (The nuke is not, it explains, serviceable in the field.) Not sure how that works when you’ve just aimed it at a Soviet tank column, but I’m just following procedure, here.

Back to firing the gun — a step not shown here is the work that goes into aiming it. Not very interesting photos, so let’s skip them. The gun itself shoots out a bunch of propellant from the back when it fires, so you have to unwind a very crude looking little firing line with a button on it.

And then you’re pretty much ready to go! Here’s the assembled Davy Crockett system (this is the large one, not the small one, but they look pretty similar).

The large one is somewhat more amusing than the small one, because loading it is quite inelegant looking by comparison:

There’s just no graceful way to load an atomic bazooka. Now you know.

Lastly, it’s time to address the obvious. Pretty much every photograph of the assembled Davy Crockett looks impressively phallic. But in my mind, the one below wins the award as “most disturbingly phallic.” This one comes from Chuck Hansen’s Swords of ArmageddonIt’s kind of hard to imagine it wasn’t purposefully staged.

The less said about that, though, the better.

The Davy Crockett system was actively deployed from 1961 through 1971. The redoubtable Atomic Audit reports that they were found to be highly inaccurate and were not effectively integrated into actual war plans. Nonetheless, according to the same source, some 2,100 warheads for the Davy Crockett system were produced, at a cost of about half a billion (1998) taxpayer dollars.

The same warhead was also used for an “Atomic Demolition Munition” which was deployed until 1989 (!), but more on those another time — they’ve got their own story.

Just a note: the NPR’s very-cool Robert Krulwich has two pretty great posts recently. The first, which would be great even if it didn’t involve yours truly, is on “Five Men Agree To Stand Directly Under An Exploding Nuclear Bomb.” Check it out, if you haven’t already. The second sounds like a Bio-ethics 101 hypothetical but was a real question for a small number of people : “If You Are Hit By Two Atomic Bombs, Should You Have Kids?

  1. The  nickname of the AIR-2 Genie  — “Ding-Dong” — would of course have taken the cake, if it were official. []
  2. Roland B. Anderson and Leonard C.  Weston, “Project Management of the Davy Crockett Weapons System, 1958-1962,” (Army Weapon Command, Rock Island Arsenal, 26 October 1964), available from the Defense Technical Information Center. On the name, see the “discursive footnote” on page 12 of the report (page 24 of the PDF).

    This report, incidentally, starts off in a highly amusing way:

    Several centuries ago, Edmund Spencer recorded that he was impressed by “…the ever whirling wheel of change.” We can but speculate what his reaction would be today, for we have seen the pace of acceleration increase a thousand times more than it has during the entire previous span of human history. This is especially true in the continuing military technology affecting weapons, equipment, strategy, tactics, and even the fundamental concepts concerning the role of military power.

    Today, we must telescope tremendous technological concepts, whose more simple tactical and strategical counterparts of a few years ago could be worked out at a relatively leisurely pace. The story of the Davy Crockett project is the recounting of such a telescoped project.

    Wow! What an intro — from Spencer to the atomic bazooka, in two paragraphs.

    The report also has a thesis that would not pass muster in any of the classes that I taught: “It is extremely difficult to draw any conclusions about the management of the Davy Crockett weapons systems’ development, except to say, it was successful.” []

27 Responses to “King of the Wild Frontier”

  1. Blake says:

    I was always we creeped out by that picture at the top. There’s just something not quite right about it. The dark vignetting, the leering, covetous half-grin of an aging, washed-up legislator. It’s sinister.

    Anyway, I the most amusing part of the thing is the fact that the timing mechanism GOES TO ZERO. For those special times, when the world has got you down, that letter from your girlfriend stateside didn’t contain the message you’d expected, the Ruskies are on your tail, and you just want to go out with a Cherenkov tinged bang, I guess.

    It’s weird to see my mention of that ground zero video in your last post take off around the internet the way it has. It only had a couple thousand views since it was put up by Kuran last year and now it’s over a million. Wild.

    • Blake: Robert Krulwich specifically told me that it was your comment that led him to that video, so congrats, and thanks! 🙂

      Yeah, I love the low-end of the timer. Are there situations where anyone would want to set it to 0 seconds? 1 second? Even 5 seconds? All of that seems too short by far, even given the small range of the warhead’s danger radius.

      It would be “fun” to calculate the bare-minimum timer setting for not killing the guy firing the gun.

    • According to this source the “light” DC had a muzzle velocity of 459 fps and the “heavy” had a muzzle velocity of 656 fps. Let’s conservatively assume that the range of hazardous effects is 400 meters, or 1,300 feet.

      So a basic linear calculation (and I’m no scientist, I reiterate) would say that with the light gun, anything under three seconds would be terribly deadly, and for the heavy gun, you could maybe get away with two seconds? But you’d be cutting it pretty close…

      Of course, if I’m wrong about the range of hazardous effects, then all that goes out the window. All-in-all, not exactly something you’d want to get wrong.

    • Ken says:

      Timers count down to zero. There was no way to set the device off unless it was fired.

  2. Jason M says:

    Those NPR links are full of a lot of alarmist weirdos with the occasional normal post. Sad that so many people are so afraid of this stuff still.

    • What I’m really taken by is how much polarization there is. You either have alarmist, all-radiation-kills-you-immediately folks, or you have everything-nuclear-is-totally-safe-radiation-is-good-for-you types. Both are superficial ways to think about nuclear risks (vis-à-vis non-nuclear risks), of course, and both lead to their own different brands of foolish conclusions. (As you can see, I’m positioning myself as a wise moderate, which is awfully convenient, rhetorically speaking. But at least I’m conscious of it…)

  3. […] HOWTO fire the Davy Crockett tiny-nuke. […]

  4. Stan Norris says:

    Acording to the Pentagon’s History of the Custody and Deployment of Nuclear Weapons: July 1945 through September 1977 the Davy Crockett was deployed in Guam (Jan 1965-June 1969), Hawaii (Apr-June 1964- June 1969), Okinawa (Apr-June 1964-Dec 68), Republic of Korea (July-Sep 1962-June 1968), and West Germany (Oct-Dec 1961-August 1967).

  5. Jon H says:

    “The advantage of having these on a jeep is that you could wheel it around pretty quickly, and you could store half a dozen of the warheads in the back. I mean, who hasn’t thought about doing this once or twice?”

    The photo of the six Davy Crocketts in the back of a vehicle shows an M113 tracked armored personnel carrier, not a jeep.

    • But it’s much more fun to call it a jeep.

      • Tom Hermann says:

        In the beginning each D/C section had a XM-28 and XM-29 assigned to a section. While stationed in Germany the jeep mount XM-28 would always get stuck in off terrain snow. The XM-28 was replaced with another M-113 and XM-29.

  6. Nuclear Tan says:

    Actually I would think the 0 timer setting actually did have a purpose if your position was being overrun you would probably be expected to destroy any special weapons in your possession at all cost.

    My favorite aspect of the man portable tactical nuclear weapons were the lack of PAL’s the W54 timer activated warhead was also the basis for the man portable SADM. Recently I read an interesting story in the book “One Point Safe” by Andrew and Leslie Cockburn. In 1977 an offshoot of the terrorist group Baader-Meinhof attempted to raid the then secret nuclear weapons depot in Giessen West Germany to seize control of a 8′” nuclear artillery shell (W33). The terrorist were aware this tactical device had little in the way of access control beyond armed guards. The terrorist used attractive females, drugs and liquor to get the information they needed from men stationed at the facility. The plan was to blow up a huge poorly sited aviation fuel tank that would flood the base with fire and in the ensuing confusion the terrorist would pinpoint an attack on the special weapons storage bunker. Fortunately the flood of flames turned out to be a trickle and the intruders were repelled.

    • Ken says:

      If you were being overrun, shaped charges were carried to destroy the projectile. The launcher was destroyed by thermite grenades. The timer counted down to zero but it would not start the countdown until the projectile was fired. There was no way to start the timer without firing the projectile.

      There seems to be a fundemental misunderstanding of the timer. Even if you could set the timer working on the ground, the projectile would not explode. The timer was a safety device to prevent the bomb from going off too early. Please note that the timer was at the base of the rear antenna dome. It controlled when the information from the antenna domes would start to be used. So, the zero setting did have a purpose, was very important and was used in every firing event but it did not cause the explosion. The timer only told the projectile when it could start to calculate it’s height in preparation for exploding. It was not just a “dumb” bomb.

      I served a Davy Crockett for 13 months in Korea in every crewman’s position. 1965-66.

      • Thanks for the description, Ken.

        Can you clarify your last point: The timer only told the projectile when it could start to calculate it’s height in preparation for exploding. It was not just a “dumb” bomb.

        Did it have some kind of altimeter inside of it? Is this what the “height of burst” switch manipulated? Can you provide any details as to how that worked in practice — e.g. was “high” set to a specific height and “low” another, or something else? I had assumed the “height of burst” switch was more related to yield considerations than a detection of actual height, but this was just an assumption.

        • Ken says:

          The projectile passed it’s burst height twice. On it’s way up and again on it’s way down. As a safety, it would not be fully ready to detonate until the rear antenna dome no longer sensed the ground and the timer ran down. The timer was a safety device. For example, if you were in a valley and firing over a mountain, you could not have the projectile sensing the mountain as it could possibly go off as it passed it’s height of burst setting in going over the mountain.

          Yes, that was what the HOB switch was for. When the radar said it was the correct distance from the ground as set by the HOB switch, it would detonate. The switch had two settings. Each was set to one specific height. We always set it to “High” in practice because, in a war, special permission had to be granted to set it to “Low”. In the projectile in 1966, there was no provision to change the yield. The yield was set at the armory inside the projectile. We could not change it.

          • Ken says:

            I was thinking about the DC weapons system and thought I could expand on some of the timer info. The timer ONLY armed the fuse at the end of the time setting. Each mark was 1/2 second. It had to be set for at least one second or the fuse would never arm. On the “S” (safe) mark, the fuse could not be armed. A spanner wrench came with the projectile. One side had two projections to set the timer and the other side had a small prong with a screwdriver tip to set the HOB and Arm Safe switches.

            No calucations were required to figure out the timer setting. Once you had figured out the range, a book with tables in it was consulted and it told you the setting. The crew man that figured out the direction, range and corrections to the guns (the DC and the 37mm spotting round) was called “Computer”. This was the actual Army designation – not a nickname. We had NO actual computers. The gun elevation for the spotting round was different than the DC round. When the 37mm was on target the gun would be “superelevated” to the much higher elevation required by the DC round. The Computer would figure the superelevation by again using the charts in a book. I personally think the need to change the elevations caused the gun to be somewhat less accurate. But then, how accurate do you have to be when firing nuc’s?

      • Jim pelszynski says:

        I served in Korea 1964-1965 hhc 3rd bde1cav div camp McGovern Davy Crockett section loader driver m113.

      • Jim pelszynski says:

        I served their also from 1964-1965 hoc 3rd bde 1st cav div. camp mcgovern m113 hq42

  7. Mike Lehman says:

    The Davy Crockett is one of my favorites. I happen to have a copy of the Service and Maintenance manual for the launchers, tripod assemblies and mobile mounts. The one here is, well, more fascinating. I vote for a full scan… 🙂

    The DC also figures in my work. The major sticking point that developed in the way of a comprehensive test ban in the course of the Geneva process that began in 1958 was over the issue of seismic detection. First it seemed likely to fly, then Teller and Latter trundled out the rather implausible but somewhat workable decoupling theory that might disguise a test shot underground if the Russians really wanted to fool us (supposedly.)

    Much was made of the immaturity of the seismic detection systems available and the various unknowns involved. In fact, AFOAT-1 was actively engaged in seismic monitoring at least as far back as 1950 (and experimentally before then.) Yes, it wasn’t 100%, but it was pretty good for the sort of tests that were being done by the nuclear powers in the early Cold War. In 1968, little in the way of underground testing had been done to calibrate against, but it was a rapidly advancing field with considerable US gov’t investment in geology and seismology during this era because of this, if you will, “seismology gap.”

    After the high-yield weapons originally favored and prioritized by SAC ended up as mostly a strategic dead end (too big, too much fallout, better accuracy in delivery made them obsolete), American weapons designers fell back on the diverse program that — ironically — the Oppenheimer era GAC had placed in motion before he left gov’t employment. And this complex R&D program had been very successful in reducing the size of weapons. IIRC without my notes [and Chuck Hansen] in front of me, the core of what became the DC was tested at HARDTACK in 1958. The 1962 test was of the finished product, slowed to service entry by the temporary test moratorium in place from late 1958 to 1961.

    So “small was beautiful” by 1962, but this trend [sorry, physical limits prevent a fabled atomic hand grenade, and who has the arm to throw it anyway?] was slowed by arms control diplomacy. It took awhile, but the folly of the DC was eventually realized, in part because one can easily imagine how much local fallout would be stirred up by burst at near contact with the ground. The NTS plume charts seems pretty optimistic if applied to what would likely have happened in a shooting war in densely populated Europe.

    So where does seismic figure with the DC? Well, the argument on DOD’s side was that the capabilities of seismic testing needed to go down to very low yields. The US was naturally ahead in this area and wanted to not miss the Russians going there, too, without detection in the event of a comprehensive test ban. Since signals from very low yield shots tend to get buried in both natural (earthquakes, etc) and human-induced (mine explosions, etc) noise, the argument was that seismic detection didn’t have the capabilities needed to verify a comprehensive test ban. This yielded a test ban between the big three nuclear powers that covered the atmosphere and oceans, as well as as space, in 1963, but not underground. The arms race also got a reprieve and went underground, with a few exceptions from the minor nuclear powers who didn’t sign the LTBT.

    I’m not certain what the smallest Soviet nuclear weapon turned out to be. Seismic detection is vastly more powerful today, with sophisticated software to screen noise out and global coverage unimaginable in the early 60s. And any nuclear program has to start off “so big” before it could even begin thinking about shrinking things down to DC size. But the Davy Crockett represents something important about why we’re still stuck with a Senate unable to ratify the CTBT.

    • Mike Lehman says:

      Uh, that should be “1958” in the third paragraph, as in “In _1958_, little in the way of underground testing had been done to calibrate against…”

      My apologies for the confusion.

  8. Ed Fox says:

    I remember being in a DC platoon while stationed in Germany in 1962-1963. We used the M-113 APC’s and our mission was to help slow down the Ruskie’s advance by firing on choke points, mountain passes, etc.

    I wonder what became of my old buddies in the 4th Armored Div, 37th Armor?

  9. ajay says:

    Of all of the many silly names for nuclear weapons system that have been given, Davy Crockett has got to be one of the odder ones, in my view

    In the US, sure. Over here in the UK we had Violet Club, Green Bamboo, Blue Danube, Orange Herald, Red Beard, Blue Steel and most recently Chevaline (which is French for “Horse Flesh”).

  10. Ken says:

    “The way the gun works is that you put a huge tube of conventional propellant behind the projectile, and then a long “launching piston.” The piston is attached to the nuke. When the conventional propellant goes off, it sends the piston flying, which in turn transfers that force to the projectile.”

    Just some thoughts about the launching piston. It was attached to the projectile by two bayonet slots. When the gun was fired, part of the propellent gas would go through a strainer at the bottom of the piston and the pressure between the piston and projectile would separate them about 13 feet in front of the mouth of the gun. What’s interesting was that the piston would then begin to tumble and fall to the earth well before the target area. As there would normally be some of your own troops between the DC crew and the target, you could kill or injure your own troops! They would be warned over the radio when to take cover – not only as protection from the exploding nuc, but from the piston.

  11. Thomas Hermann says:

    I was assigned to the Davy Crockett section Hq Co 3/36 Inf. Regt. West Germany in March 1962. The Davy Crockett had been assigned to West Germany in Dec. 1961 and most battalion commanders didn’t know what to do with this system. Our section was assigned a XM-29 that was stored in a modified M-113 and a XM-28 jeep mounted weapon. The XM-28 was removed from our section in Nov. 1962, it was replaced with another XM-29. The XM-29 originally did not have a spotter gun and we used M-390 high explosive rounds for spotting. Figure 21 shows the M-113 with six pods for M-390 training rounds. In late 1962 the M-113 was modified again with one roll of pods removed and a space was made to store spotter round crates. I have photo’s of the modifications that were made. I had heard when the XM-28 was removed from our section it was reassigned to the Airborne division they used the port-a-pack when jumping out of a airplane.
    I was sent to a four week class at the Combat Arms School in Vilseck, Germany. We were taught how to fire four nuclear rounds off in ten minutes. We also learned how to survive radiation fall out, how to store nuclear war heads in a field situation. One of our biggest threats came from the Russian teams called Spetsnaz, know as the hunters of the Davy Crockett teams.