Two Strange Project SPIW Magazines (Video)

Today we are taking a look at two unusual magazines from unusual firearms. These are a 60-round double-column mag from a Springfield 1964 SPIW bullpup and a 50-round box magazine from an AAI XM-19 serial flechette rifle. These have both been covered on the blog before, but I wanted to give them some video coverage…

For lots more information on Project SPIW, the best source is “SPIW: The Deadliest Weapon that Never Was”.


      • Harrowing- put the back of your hand against your forehead adopt a “luvvie” sort of Oscar Wilde, limp type stance and look at the sky whilst pulling an expession that is befitting of tragedy, and say ghastly, simply ghastly upon hearing news of Clintons impending demise in the recent U.S election for example.

        Is the rear “finned” section of that Fletchette in the link you posted made out of Polymer?

        • “Is the rear “finned” section of that Fletchette in the link you posted made out of Polymer?”
          Sadly, I don’t know. AO-27 and its ammunition was not adopted, but concept of arrow-like bullet was not totally abandoned.
          Дворянинов, in second half of 1970s, designed 4,5/10x54R based on 7.62x54R case, you can see photo here:
 (page 7 of pdf/page 58 of original) together with experimental fragment of belt for machine gun.
          Experimental batch was produced by Plant No.188 (Novosibirsk), universal machine gun and sniper rifle were created for that cartridge. Project was ended after it was revealed that “arrows” are sensitive to side wind and out of production tolerances.

          • I can see the elongated arrow like bullets you mention in the pictures, 6.5mm Carcano like, which is supposed to have good penetration and accuracy etc.

    • I do think the Tandem magazine might be able to be used in some form of AN94 type rifle configuration, as oppose as an extra feed solution. The layout could perhaps facilitate the twin firing, two shots is better for hit probability lark via the barrel moving back over the first to arrive inline with the second as the bolt is returning to the first- Which means it engages with the second now.

    • Thermal clips eh, nice. There’s some interesting… Concepts, put forward in these video games/films etc isn’t there.

      Maybe one day guns will shoot out a coil of “Moon” dust, forming a plasma rail to propel a projectile via acting as the weapons barrel. Endless possibilities, he he.

          • Hmmm… An external accelerator. Imagine explosive reactive armour, in that it explodes outwards to lessen the impact/inward explosion of an incoming projectile. Muzzle flash is an outward explosion, sort of. If there was a counter explosion, around it. Perhaps more of the energy expended outwards in the muzzle flash would be directed behind the projectile- Giving it a boost, without increasing barrel length. Physically achieving this may not be so practical in small arms, in relation to the scale of the “accelerator pack” required. Might have more potential for artillery. Interesting concepts to ponder, exploding air around the muzzle type thing before the other “explosion” exits the barrel, timing would be important. Maybe it would create a vacuum which could be beneficial, interesting stuff. Create a super cavitation, “bubble” for a certain distance, increasing the projectiles velocity via less air resistance and/or something- Open air V3 cannon effect. Worth thinking outside the box probably, already sounds a good science fiction idea 🙂

          • Have you ever seen a vortex gun, sound wave doughnut projectile… Wonder if you could magnetize iron filings and blast them out somehow, somehow leaving a… Magnetic pull trail, an invisable catapult for a magnetized projectile. Coil gun “ray” Anyway, all good he he.

          • “Open air V3 cannon effect”
            If you want shorter time between shot and impact, consider rocket propelled shells.

          • I like rocket propelled shells… But I think if the muzzle blast could be directed, behind the shell more when it leaves the barrel it should gain added oomph. Not exactly sure how to achieve this… A sequence of exploding doughnuts, that the shell passes through. Or something, something similar but not- ERA principle though’ish Possibly a rocket “shell” being propelled by a rocket motor through said doughnuts without a gun. A shell, that releases exploding doughnuts behind and around it’s primary source of propellant. Kind of fancy a doughnut.

          • So if we take that and mix it with the other in a bowel and add sugar we perhaps get, for 155mm Artillery: A barrel, which acts as such, but also as a spigot for doughnuts- Explosives encased in plastic in a doughnut shape, these are attached to, and arranged in the configuration of a telescopic ladder.

            Thus the largest external diameter doughnut is at the bottom and the smallest at the top, each having a central ring of matching and corresponding diameter to the spigot/barrel exteriors, in a manner that allows each one individually to move up/down it freely.

            Now prior to firing artillery gun as per, the top of the uppermost doughnut will be inline with the muzzle, with each other one stacked beneath. The “telescopic ladder” will sit via it’s extended twin tubular bases, which end in stop rings. Inside a correspondingly twin ported and vertically drilled gas block that fits around the barrel at a point which allows the stacked doughnuts to sit around the spigot as above.

            Upon firing gas acting beneath the shell enters the ports and into the tubes which make up the telescopic ladders sections, this extends the ladder in a manner that puts the bottom of the rearmost doughnut inline with the muzzle via the ladders design facilitating such an extension before it stops.

            It also activates a sequential detonation of the doughnuts in incremental stages from bottom to top, the top doughnut is say 10ft from the muzzle at this point with 1ft increments between each one I.e. Steps on the ladder, the bottom doughnut explodes just as the bottom of the shell passes through it’s ring and each addtional explosion is so synchronized- theoretically giving additional oomph via redirecting the muzzle blast behind the shell and with each increment adding to the overall propellant force by the time the shell exits the entire arrangement.

            I have heard about the steam powered “V3 cannons” but I am thinking of something more portable, I think.

          • There’s a telescopic ladder,
            actually it’s steps are wider at the top but you get the idea.

            Variations on it, could be… Make it a sort of er, exploding sabot. In this configuration the top doughnut ring is a bullet trap like a rifle grenade and thus is extends the ladder by virture of the shell pushing it because said trap sits atop the muzzle, with the ladders base being affixed to the guns barrel.

            This time the explosion sequence is top to bottom in that each explosion blasts the previous one towards the shell. This is happening during the extension of the ladder, when the explosions have taken place the ladder at maximum extension is over extended and because the trap part is in two sections the ladder in it’s entirety falls away as the sections pop out of each other.

            The ladders bottom attached the barrel, could be by an attachment which facilitates unattaching them, itself attached to the barrel. So for a 105mm you’d attachment the attachment, then per load the gun as normal then load a sabot, by dropping it over the the barrel so it’s legs fit into the attachment, lock them in by operating a lever.

            The weight of the ladder could not be sufficient enough to detonate the round initially by impact force obviously.

            Each doughnut is built like a Claymore mine to direct the blast more in a specific direction, object is that of mortar bomb propellant rings- Greater range.

  1. Seeing this reminds me of that little blurb about the fiberglass sabots on the flechettes.

    Why fiberglass? Would regular plastic just get completely obliterated on firing before the projectile leaves the barrel?

    That said, has anyone ever 3D printed a .30 caliber sabot to house a 5.56 bullet? Or am I just describing those SLAP rounds?

    • There’s these “Polymer” tipped bullets around nowadays they don’t get obliterated as far as I am aware, I don’t know what kind of “plastic” they are made from- Polymer? If so, perhaps that is what sabots are made from, .30/.22 ones etc. Don’t know much about plastics personally. Do 3D printers print Polymer. Are there different types of Polymer even. Inline BP muzzle loaders .50 cal tend to use sabots, shotgun cartridges use a sort of plastic sabot. I’ve wondered exactly what sort of plastic they use myself, versatile stuff “plastic” isn’t it, plastic kettles don’t melt etc. Polymer clay… Modelling stuff, Sculpy- Maybe that would work for sabots. 3D printers may well print in Polymer, handy bits of kit those things aren’t they.

      • You can buy .30/.22 sabots out of interest, I once thought of putting 3 12g Fletchettes into one, stagger the “fins” to get the .22 type diameter, in a .30 carbine loading- Hypothetically.

      • “I don’t know what kind of “plastic” they are made from- Polymer? … Do 3D printers print Polymer. Are there different types of Polymer even.”

        I always assumed that most people would have figured out that the word “polymer” –as used in the firerms trade– was simply a marketing term that was selected because the commonly understood catch-all term “plastic” was judged to have a negative connotation to gun buyers. It’s just about the most inexact word that could have been chosen, a general molecule configuration covering such a wide range of substances, but hey, it sounds technical and somewhat mysterious (at least to those who never took a chemistry class in middle school) so there it is. Perhaps it’s somewhat a shame that the corresponding term “monomer” never made it into common vernacular.

        As I understand it, “polymer” –as specifically used in the gun trade– generally refers to any thermoplastic, while thermosetting plastics are commonly (if inaccurately) referred to as “bakelite” (especially if colored light brown). I’ve not seen the term “FRP” ever used, which is a common term in the kind of non-gun circles where “polymer” in general usage is just as likely to be a liquid as a solid.

        It’s kind of funny that disposables such as plastic shopping bags or milk jugs will be labeled with a more precise material composition (e.g., “high-density polyethylene”) while expensive items such as firearms get slapped with the almost-meaningless “polymer” label.

          So it is somewhat like using alloy to describe any metal parts, whatever it is bronze, Zamak, steel, titanium-alloy or any other.

        • More proper term is “Engineering plastics”

          Personally, I do not feel resistance towards their use on firearms as I worked with them (also outside of FA use) to degree of satisfaction. It is just a matter of mating the type of material to intended purpose. They are fine, but it needs some initiation and occasional advice from moulders (and mould-makers).

          Btw, their greatest enemy is not as much heat as is extreme cold. Then they just snap without warning.

          • I don’t agree with that Wikipedia article at all, starting with its premise that there are two distinct types of plastics — “engineering plastics” and “commodity plastics”. Of course engineering is free to use whatever material meets its design requirements. I couldn’t help notice that the list of “engineering plastics” left out PVDF (Kynar), one of the most widely used industrial plastics due to its chemical resistance and other properties.

    • “regular plastic just get completely obliterated on firing before the projectile leaves the barrel”
      Soviet “arrow-like” bullet were fired from either smooth barrel or rifled barrel but with low angle of inclination (1° inclination against ~7° as used in classic bullet-launching weapon), so far I know this rifling has to make spin to help sabot discharge rather than stabilize.

      For all which prefer 1turn-in-…” style: 1° inclination barrel .30″ caliber is 1-in-54″ (If I don’t make any mistake)

  2. FWIW: Here’s is the evolution of the first-generation Springfield SPIW’s tandem magazine design.

    First, you have Richard Colby’s design.

    Frederick Reed came up with the improved version that Ian displays in the video.

    Here’s a related patent from Robert Meunier for the bolt stop used with the tandem feed magazine.

    Springfield’s bullpup layout was denounced by the testers. So the second-generation Springfield SPIW used a conventional rifle layout. This follow-on design even survived the closure of Springfield Armory, and its development was subsequently handed over to General Electric.﻿

  3. I have a similar mag to the lower one but with one wider roll spring and one rivet.
    I think that the rivet was probably the weak point of this design

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