Be Ready for the Western Front Offensive of 1919 with the WWI Pedersen Device

In the early winter of 1918, it seemed as though the Boche wouldn’t stop, and the war was sure to continue on into 1919. New, secret weapons were needed to complete the victory over Germany, and one of these was John Pedersen’s “device”, officially called “Cal. 30 Automatic Pistol Model of 1918”, a drop-in replacement for a standard (but modified) Model of 1903 Springfield rifle that would give every American infantryman autoloading firepower for close range engagements in the expected 1919 offensives.

You can learn more about the Pedersen Device, as it’s now called, by watching the Forgotten Weapons video below. Also from Forgotten Weapons is a rare shooting video for the Device, embedded in the post at this link.

The Pedersen device wasn’t a complete dead-end, or at least the ammunition wasn’t. Even by 1919, the Army started to think that the .30 Pedersen cartridge did not have enough range, and began a program to improve the range to (a rather optimistic sounding) 500 meters. To do this, experiments were conducted at both Frankford Arsenal and Remington (there, by Pedersen himself) with heavier 90 gr bullets instead of the original 80 gr FMJ, and muzzle velocity increased to about 1,500 ft/s versus the original 1,300 ft/s. To do this, the new rounds needed longer cartridge overall lengths to allow more space for the propellant. Frankford’s design used a lengthened case, but it was the Remington/Pedersen design – which was used in the Browning 1921 patent rifle, and is commonly called “.30-18” – that became the one real legacy for the Pedersen device. It seems that at some point, this cartridge made its way to France, and seems to have become the basis for the French 7.65x20mm Longue caliber used in the Modèle 1935 pistol and MAS-38 submachine gun.


Left to right: .30 M1906 Ball, .30 Pedersen as would have been issued in 1919, .30-18, 7.65 French Longue, and modern production .32 ACP and .45 ACP for scale. Note how incredibly similar the 7.65 French Longue and .30-18 cartridges are.


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


  • valorius

    I love the forgotten weapons channel. I watch at least 1 hour of his videos a day while im watching my daughter.

    • A bearded being from beyond ti

      Is she watching it too?

      • valorius

        She doesnt watch much, but she listens…i hear her say gun related things sometimes that throws her mom for a loop 😀

        • crackedlenses

          Sure sign you’re raising her right, lol.

          • valorius

            Much to her mother’s chagrin. Her mom is very girly-girl. 🙂

  • A bearded being from beyond ti

    Ian comes across as such a nice guy. Thing i like about his channel (and hickok45) is that their videos aren’t filled with obnoxious intros, cheesy rock or wobstep or some tryhard 0perat0r crap.

    • David W.

      I’ve met Ian, and you’re right. Super nice guy.

      • A bearded being from beyond ti

        Give him all you money so he can make more videos, m8

    • Bob

      Yeah, one of my ex coworkers and I were at odds because I would watch Hickok45 while he would rather watch FPSRussian. Different strokes for different folks… But he’s just wrong.

    • Joseph Goins

      No intro (e.g. hickok45) is good
      A short intro (e.g. CaptainBerz) is neutral.
      A long intro (e.g. sootch00, Military Arms Channel) is bad.
      An annoying intro (e.g. James Yeager) is terrible.

      My preference is a no frill channel with excellent content. Typically, the trade off is going to be a low quality video. My favorite is The Immortal.
      youtu . be/jwJPKyu2QTY
      youtu . be/u3BUeTM4_4E

      • A bearded being from beyond ti

        Yeah i really like channels that avoid intros, outros, excessive transitions etc. That might work for TV but this isn’t TV now is it?

        Althoug Hickok45’s videos can get kinda dull at times, they are a tad bit to long.

        • Joseph Goins

          They are short by Nutnfancy standards. That man can and has given us a feature-length “film” on a fanny pack before.

          • A bearded being from beyond ti

            So I’ve heard.

  • Fruitbat44

    Fascinating. A real “what if” of military firearms/history. The dressing up element did add something to the video, and did enable Ian to display the specialised webbing associated with the device. Although somewhere I could the ghost of a long dead Sergeant-major screaming, “Get your hair cut you ‘orrible little man!” Thanks for sharing.

  • Don’t forget that Pedersen Devices variants were developed for other rifles as well. These would would have fit the M1917 and the Mosin-Nagant.

    • AirborneSoldier

      Not unless the rifles were highly modified. Never read of nor seen such a mod in any leading periodicals or references, or firearms, but then again, i am surprised every day. Id like to see that.

      • Yes, the rifle actions would have required a new ejection port cut into the left receiver wall, just like the M1903 Mark 1 hosts.

        • Here is one of the modified M1917.

          • Julia’s also sold a Mosin-Nagant that was modified, but without the accompanying Pedersen Device.

          • Here’s a close up of the receiver modification on the Mosin-Nagant.

  • Joe

    Someone needs to update the concept for the Remington 700, but other than 7.62 Mauser or 7.63 Tokerav I can’t think of a common .30 caliber cartridge that would work, and those two aren’t exactly common. Looks like they wanted to retain the 30.06 capability (magazine), but a bottom feed top eject should be possible.

    • ostiariusalpha

      If the box mag isn’t a requirement, some type modified design could accommodate the .30 Carbine round. The main difficulty would be fitting a more robust action into the device, as .30 Carbine is too powerful for straight blowback.

      • Tassiebush

        Maybe. 32acp or .32s&w long. Both are already proven in chamber adapters. It could also be matched with a detachable mag conversion kit for floorplate models to make switching quicker and you’d just have bottom feed for the device to reduce need to permanently alter original firearm. Not sure how to make it semi auto like the original. They modified the trigger on rifles to make them semi auto rather than full auto which would otherwise have been the norm.

        • ostiariusalpha

          Those .3125 bullets are a little oversized for the rifle’s bore; not that they couldn’t compress to fit, but it would use up a larger portion of the little case’s propellant in doing so and leave you with less muzzle velocity.

          • iksnilol

            I doubt .32 acp bullets would be problematic through a .308 bore.

            As long as it isn’t a super tight match barrel.

          • ostiariusalpha

            It’s mostly the velocity & energy loss that makes them less than suitable; the .32 ACP isn’t exactly a super energetic speed king to begin with. Now, if you were to shoot them from a Mosin rifle Pedersen device, you might actually get some benefits from a longer barrel.

  • AirborneSoldier

    I keep looking for the Pederson device at a garage sale or junk store. I dint think my mk1 will ever have one though. Nice article, etc,

    • Scott

      If you find one, be prepared to pay thousands of dollars. Fewer than 100 are believed to have escaped Uncle Sam’s destruction order.

  • Tassiebush

    Seems like in the din of the western front the low noise of this might have been fairly discreet.

  • retfed

    Is there film of one of these actually being fired? I’ve never seen it, and I sure would like to.

  • smitty26

    Cut off the pony tail to look serious.He looks like a Dutch soldier from the 70 ths