Pancor Jackhammer Mk3

John Anderson was a Korean War veteran who became interested in developing a high capacity, selective-fire combat shotgun for military use. He designed what became known as the Pancor Jackhammer, a fully automatic, gas operated, blow forward, drum fed shotgun. Three working examples were made, two tested to destruction by HP White Labs, and one which Anderson retained for himself. The project ultimately failed for lack of funds when the military decided not to pursue its development – but not before Anderson began working on an improved Mk3 version. The Mk3 never reached completion, but what we have to look at today is a partially completed prototype of it. This gun never had a firing mechanism installed (and appears to be unfinished inside as well), but is registered as a transferrable machine gun.

22 Comments

  1. One correction: the design of the grooves on the cylinder is actually functional; it’s the design as specified on the Jackhammer patent, and uses two cams. The one-cam one-groove design used on the Movie Gun Services Jackhammer is just a different design.

  2. “This gun never had a firing mechanism installed (and appears to be unfinished inside as well), but is registered as a transferrable machine gun.”

    If that doesn’t sum up the NFA and ATF, I don’t know what does.

    • It’s called “OH NO, SOMEONE COULD FABRICATE A FIRING MECHANISM AND TURN THIS ODD DEVICE INTO SOME COUNTRY-DESTROYING SUPERWEAPON” fear.

        • Until the narrative gets destroyed by a lawyer. “Can you actually operate the weapon in front of the court in its current condition? If it fails to fire as is, then you have committed perjury!”

  3. I have lost track of the ‘attempts’ at an automatic or multi round shotgun (the configurations etc almost endless / every possible types have been ‘proposed’) – which obviously an attractive concept. But have yet to come across a successful one – beyond or a viable successor of the frankly somewhat basic pump action type. Can anyone point to or suggest one (being genuinely interested – both as a concept and practical- commercial ‘thing’) ?

    • AA12 and Usas12 were close to fulfiling that requirement, but got legally destroyed right in the start, obviously the authorities concluded even in semi auto they potentially were too dangerous (to them) for citizens to own, as effect they have, I suppose, in close range very much is like full auto from rifle.

    • Firstly, I would say similar spraying effect might be attained using sub-machine gun, which might be make shorter (easier to maneuver), have generally greater effective range and if have selector might be used for firing single bullet at wish for situation when spraying is not desired. Nonetheless as already said there were attempts to create shotguns able to provide full-auto fire.
      If you are interesting in such weapon I suggest examining U.S. Close Assault Weapon System contenders, but with disclaimer that they were not limited to usage of already existing ammunition, among others HK CAWS https://modernfirearms.net/en/shotguns/germany-shotguns/hk-caws-eng/
      For full-auto shotgun using normal 12 gauge ammunition see Special Operations Weapon https://guns.fandom.com/wiki/Special_Operations_Weapon

  4. The problem with shotguns is that the ammunition is short range, and quite large and bulky. As a police weapon, it had few peers because engagement ranges were typically short, and gun battles/ fire fights were of short duration for the most part.

    In military use, the shotgun has always been a niche weapon, appropriate to its chief shortcomings. For dense triple-canopy jungle, and in some urban scenarios, or when the armed forces personnel are engaged in basic policing operations or posting static guards or whatever, then yes, shotguns made an appearance.

    One aspect of a purpose-built “modern” fighting shotgun is rather like the obstacle to building an “assault rifle”: Insistence on 12-gauge shells–2-1/2″, 2-3/4″, 3″ etc. makes the resulting weapon heavy and a bit awkward. Compare the .276 7x51mm Pedersen-caliber M1 Garand with the .30-06 U.S. rifle, caliber .30 M1. If ammunition could be constructed in a 20-gauge or smaller format, which has thus far proved elusive and confined to turning a 20-gauge into a short-range deer rifle for hunters and a .410 into a novel challenge for Turkey hunters, then the shotgun might be redesigned as some sort of short, compact bullpup.

    Winchester toyed at developing a prototype “submachine shotgun” in the 1950s and 1960s that was a select fire 28-gauge. That would be a flechette-firing .55 caliber submachine gun… as opposed to a .45 caliber M3A1 or a .355 caliber Sten MkII or Uzi… Perhaps not that much of an “improvement?” Another attempt at an Uzi with properties of a shotgun emerged in the South African MP7, reviewed by Ian as among the worst firearms he’s handled?
    https://www.forgottenweapons.com/techno-arms-mag-7-shotgun-shooting-history-disassembly/

    https://www.forgottenweapons.com/shooting-the-techno-arms-mag-7-properly/

    As an easy-to-use by untrained people firearm, Winchester and Robt. Hillberg developed the “Liberator” reviewed by Ian at the Cody Firearms Museum:
    https://www.youtube.com/watch?v=PQK9JNsrq_8

    Imagine a giant-sized box-lock Lancaster pistol with a Tranter trigger (The “Howdah” of the battlefield 1 video game franchise…) but in 16-gauge instead of .476 or .450.
    Seems promising, but still a niche weapon… And one that for military purposes was already fulfilled by pistol-caliber blowback machineguns at a time when the assault rifle was about to “go large.” The only possible customer would have been civilian sales–unlikely–or the police/law enforcement market, which was already awash in pump-action and SxS shotguns and didn’t need a four-barrel shotgun. Then, of course, it was “upgraded” to 12-gauge, which then negated the idea of a more controllable 16-gauge or even 20-gauge…

    Another “also ran” or “honorable mention” was Hockler u. Kech’s G-11 lookalike CAWS “weapon system” based on–yet again–the 12-gauge. That, in turn, seems to have developed attempts at a shoulder-fired grenade launcher, the XM29 OICW and the idea of proximity fuzed mini-grenades like the South Korean and French PAPOP and Inkunzi PAW or Neopup and kindred grenade launcher prototypes.

  5. All of the practical considerations outlined by the previous commenters don’t matter. Why?? Because this was one of the best guns in the old PC based “Fallout” game series, it’s really cool looking, and I am a gunsmith with the machine tools and knowledge to make it work. Sadly, I do not have the gazillions of dollars required for “shall not be infringed” to apply to cool guns like this one.

    • Played Fal.2 (never finished, its in progress),
      there is even G11 and CAWS – I really like that 90s vibe when in games and movies you had a variety, stemming from the 80s, and not every gun is AR15 derivative, like today.

      If you have enough skill, time and dedication, you could make one for yourself, at least by external look; if you don’t, that could be a potential waste of your machine tools and knowledge. Who knows, maybe one day your creation could end up in such auction.

  6. The use of a large caliber is justified ONLY if you really need a large projectile.
    And such a large projectile can only be a grenade. All other options for equipment for military purposes are either insignificant, or are covered (and much better) with automatic weapons for pistol or rifle ammunition.
    Similar, but with a different sign, for a police weapon. Shotguns are as effective against soft targets at close range as they are indiscriminate, which means they are dangerous by accident.
    The result, de facto, is that shotguns are used either as a key or as a means of reduced lethality.
    A good example is the French special forces police.
    Who bought Molot-12. And they use them almost exclusively as hammers for knocking down doors and knocking down the most persistent assholes. If I’m not mistaken, they don’t even have live ammunition on their supplies.

    And given that 37mm (which still has a set of properties for 12 unattainable ones) copes with a non-lethal function (like the master key) much better, there is no place for a shotgun at all, except for civilian use.
    And a civilian user (except for tactical masturbators and filmmakers) also does not need such a mega-blaster. Since (for example to me) the obrez of a double-barreled gun or a pump is much preferable.

  7. Shotguns are simply breaching devices for military they can open doors of all varieties with minimum power for that breaching round

  8. “The functioning Jackhammer has gone through three or four owners since then. (Paraphrased)” This phrase has no right to remind me of Stephen King’s “Christine”, yet…

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