Firearm Showcase: The Winchester SPIW Flechette Rifles at the Cody Firearms Museum – HIGH RES PICS!

In January, just before the 2017 SHOT Show, I got the opportunity to travel to Cody Wyoming to visit the Cody Firearms Museum at the Buffalo Bill Center of the West, to see some of their rare firearms and bring photos of them to our readers.

Today we’ll be looking at not one, but two guns. These green retrofuturistic rifles are in fact two very rare Winchester “soft-recoil” SPIW prototypes. The SPIW program was Springfield Armory’s last gasp attempt to provide the US Army with a follow-on to the M14 rifle, a too-ambitious program that combined high capacity flechette-firing rifles with multishot underbarrel 40mm grenade launchers. Winchester’s entrant was an extraordinarily lightweight rifle sporting a 60-round drum magazine and a quasi-hyperburst action that stored the recoil in a spring in the chassis until the end of a burst had been completed. Unlike rifles that employ a similar idea, such as the AN-94, the Winchester SPIW had a very modest cyclic rate of about 700 rounds/min.

Although the individual rifles themselves were quite light (my guess is about 6 pounds or so, with the drum), the fully loaded SPIWs with bipod, grenade launcher, and other accessories were supposed to be about 12 pounds!

I can say that I never have held a military rifle that felt as cheap and disposable as these Winchester prototypes. At the time, I was overwhelmed by a feeling that in some alternate universe, soldiers fought in an atomic World War III with weapons like these, lifespans of men and rifles alike measured in just hours or even minutes. It’s not so hard to imagine, either, that Winchester’s Liberator shotgun from about the same time was perhaps designed to fight the next war after that!

If you’re interested in seeing more of the Cody Firearms Museum, I highly recommend taking a trip out to Cody, Wyoming to see their awesome and extensive collection. They have over 7,000 firearms, about 4,000 of which are on display. In particular, if you have an interest in Winchester firearms and their history, Cody is the place to be. If just a visit isn’t enough for you, then check out the museum’s 79-page book, which highlights some of the finest pieces in their collection!

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at


  • Jared Vynn

    That green looks like it was taken straight out of M.A.S.H. love the way that rifle looks. Is that a tang safety behind the rear sight?

    • Twilight sparkle

      I think it is since the selector on the left appears to have positions for semi 3 round burst and full auto but not safe

      • Jared Vynn

        That’s what I was thinking as well. I kinda like the idea of a safety seperate from the selector.

    • Yes, see part number 118 in the patent drawing once the TFB moderators approve me earlier comment. There is a separate button (part 110) that switches the trigger linkage so it can fire the optional grenade launcher instead of the rifle.

      • Jared Vynn

        Now that is brilliant, would be great for an underbarrel shotgun.

  • Ron

    That is pretty cool

  • DW

    After all these years you tell me the gun is actually GREEN?

  • Johnsmyname

    This is very cool. Something about a drum fed flachette gun that just makes me smile.

  • TheNotoriousIUD

    Im guessing ammo does not exist.

    Any available video of one being fired?

    • Individual 5.6x44mm XM144 cartridges exist, but it is a collectable item. I frankly doubt anyone with with a surviving Springfield Armory or Winchester SPIW wants to risk shooting it, much less pay for enough ammunition to do so.

      • MPWS

        I recall to get the muzzle velocity the chamber pressure was extremely high.

    • I have a couple of rounds for it, heheh.

      • TheNotoriousIUD


      • Old Vet

        How about a pic of the round itself??

  • Some Guy

    Looks like something from FALLOUT.

  • Twilight sparkle

    Is that an xm177 style moderator on the end of the barrel?

    • No, it is a combination flash hider, muzzle brake, and sabot stripper.

      • The device on the second rifle appears similar to a Colt moderator, to me. This would make sense, as the SPIW flechette rounds were supposed to be ungodly loud.

  • MPWS

    It kind of resembles PPSh41 except it is wrapped in plastic which owes it its low mass. I wish to see the internal mechanism; but I understand museum does not allow guns to be stripped open.

  • Joey JoJo Jr.

    Very interesting. Blowback, recoil, or gas-operated?

    • It is gas-operated, but borrows from the differential recoil concept.

  • roguetechie

    Nathaniel, please tell me that eventually you’re going to get us pictures this good of the 2nd generation Springfield SPIW

    • I hope I’ll get pictures much better than this of the Springfield SPIWs.

  • roguetechie


    Do you have a list of patents or any links to detailed information on the gen 2 Springfield spiw?

    The one which is “telescoped bolt”

    • I can’t think of any of the Springfield 2nd Gen rifle patents right off hand. If I have them, they are on my 5.56mm Timeline page.

      However, I did find one for Springfield’s belt-fed SPIW LMG, shown on Page 50 of the Collector Grade book.

  • Another bit of forgotten history is that Winchester had a Springfield Armory contract as early as 1961 to develop the “soft recoil” concept, predating this SPIW prototype.

    Springfield Armory also contracted with Winchester to rechamber five of their Lightweight Military Rifle prototypes from .224 Win E4 to the 5.6mm XM144 SPIW cartridge. At least one of these was later rechambered for the XM144-WE4 cartridge.

  • noob

    why does the selector go “FA, 1, 3”? Select Fire AKs also seem to have “Safe, FA, 1” in contrast to the “western” style “Safe, Semi, FA” selector, so it’s interesting that this winchester has such a combloc style selector.

    is the ergonomic reason that if you yank it in any direction as far as it will go, you get anti-ambush mode, but for deliberate shots you have to carefully select “single fire” in the middle?

    • iksnilol

      Full auto is “how to get killed in an ambush” mode.

  • b0x3r0ck

    Anyone have blueprints of this rifle?

  • Tassiebush

    In another happier parallel universe we buy something like this in local shops just like a toaster for about $150 and use them for stuff like blasting vermin.

  • anonymouse

    Any pics of the ammo?

  • Tassiebush

    Haha no vermin vermin. Seals eating salmon out of fish pens, quolls eating chickens and stuff. 😉

  • El Duderino

    If you squint, it’s an OD green SU-16 with a Magpul D60.

  • Gonna be taking some photos of ammo tomorrow. I’ll try to get a couple of these rounds, too.