Firearm Showcase: Winchester Mystery 1966 Underbarrel Grenade Launcher 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.

On Wednesday we looked at a Winchester mystery rifle, and today we’ll be looking at another mystery gun from approximately the same time, this time an underbarrel grenade launcher. The launcher is marked:

CAL. 40MM     #1B 1966

Which helps alleviate the mystery somewhat. The launcher itself is a simple sliding barrel design, similar in concept to the later AAI M203 which has since become the ubiquitous US Army underbarrel grenade launcher. The launcher appears to be made out of aluminum with a brass-like anodizing, and beyond that, there’s not much we know. Based on the date, this launcher would had been made after the abortive XM148 underbarrel grenade launcher, but before the June 1967 solicitation for its replacement. Further, no mention of a Winchester single-shot grenade launcher is made in either The Black Rifle, or SPIW: The Deadliest Weapon That Never Was.

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


  • It may be a spin-off of the three-shot launcher developed under contract for Springfield Armory’s 2nd Gen SPIW.

  • Mike

    I want to see this on an M16

  • Pandaz3

    I was in 2/3 Inf Bn, 199th LIB in 66-67, we had numerous experimental weapons including several under slung and also stand alone M-79 like grenade launchers and that bazooka replacement the XM-72 LAW. We had so many because we were the closest Infantry to Saigon at the time, and the team monitoring the test weapons could visit now and again. For some reason I seem to recall a long cocking lever on our under slung launchers, I seem to recall that shooting they were okay, but that lever got hung up in foliage. The Beta Test Experimental weapons were some times a Pain in the Posterior for the troops while carrying them. but the Company Commanders had to write a lot of additional reports about these weapons systems. They were pretty busy anyway and these added a lot of administrative burden. I was a Medic, I learned that the Infantry was a lot of work. Lots of snakes, spiders, and what they now call IED’s. Always Mud.

    • That was likely the Colt XM148 grenade launcher.

      • Pandaz3

        Maybe so, it just seemed a little different in my memory, but Mr. memory has been going AWOL of late. On another note I did visit the museum in Cody this past summer, I was looking for a M-14 A1 and was surprised that they did not have one. I have my first DD 214 registered in the courthouse there in Cody so I had been to the Museum before

  • LazyReader

    1966, looks like it was made in 1866

  • tsubaka

    in which way does it mount on an m16?
    It looks like it use the barrel and the bayonett mount (pic 3-4) but in this way the trigger seems weird

    • I am not certain it mounts to an M16. It might mount to an SPIW.

  • James

    Only 4k guns on display? Yall need to check out the J.M. Davis gun museum.

    • Old Vet

      Went there a couple of times in the late ’70’s, but can’t seem to remember much about it…..too many miles have passed since then.