Weird Magazines, Vol. II: The Hill Submachine Gun

Since the first article received a fairly enthusiastic response, I have decided to continue the series on unusual firearms feeding mechanisms. Many of the devices I will cover are associated with equally interesting firearms, but for the sake of brevity I will be mostly talking about the magazines themselves. One of the more unique and important designs is the Hill H15 submachine gun, which used a transversely mounted magazine of a design that would reappear with the successful FN P90 PDW/SMG. Matt at the Historical Firearms blog writes:

Developed by engineer and inventor John L. Hill the Hill H15 submachine gun was decades ahead of its time. Hillbegan developing the idea for his futuristic looking gun in the late 1940s but it wasn’t until the early 1960s that he built his first prototypes.

The H15 feeds from unique clear plastic single or double stack magazines which were loaded into the top of the receiver. This magazine was preloaded and sealed with an aluminium cap and magazine capacity varied with length. The H15 was chambered in 9x19mm and .380 ACP and was intended to be fired as a pistol. Its rate of fire was approximately 400-500 rpm making it quite controllable. It did not have a semi-automatic capability and had very few controls with a non-reciprocating charging handle and an unusual ambidextrous crossbolt safety with the safe position in the centre.


Hill’s patent for ‘Gun with ejection through hand grip’ shows how the magazine interfaces with the ‘transfer disk’ which positions the cartridge ready for the bolt to chamber and subsequently eject. (source)

The visual similarities to the FN P90 are obvious. They both utilise a horizontal, longitudinally mounted feeding system. The main difference being that a ‘transfer disk’ or ‘turntable’ feeding system (seen in images #5 & #6) is incorporated into the action of the H15 rather than the magazine as with the P90, which has a spiral feed ramp rather than the ‘turntable’. Another shared characteristic is the weapons’ ejection, both drop spent cases from the bottom of receiver through the grip. These similarities are more than coincidence however, Hill was invited to the FNfactory in Liege in 1963 and a prototype of Hill’s submachine gun was left with FN for a number of years and was no doubt photographed and examined before being returned. It is very likely that design cues if not specifics were taken from Hill’s design as two of Hill’s patents are cited in FN’s patent for the P90′s feed system.


This patent shows that Hill’s early designs also had side mounted magazines (source)

The Hill SMG is a fascinating article in its own right, and certainly deserves its own treatment; therefore, I will most likely be doing a more in-depth article on it later. This magazine design, as Matt notes above, led directly to the FN P90, and has as a result become one of the most successful non-standard magazine configurations in history.

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


  • Gjert Klakeg Mulen

    FN P90: The early years.

    • Anon

      Ah, they shrink up so fast

  • wetcorps

    Do the ZB47 next! 🙂

  • FourString

    Dammit now I want to buy a PS90. Thx Nate >.<

  • Anonymoose

    In the 1960s they were still bothering with carbines in 9mm and .380? This would be perfect in .30 Carbine…

    • Evil13RT

      9×19 is short so it makes the gun narrow.
      Pistol calibers were also cheap, common and plentiful because of the massive civilian markets for them. Always a consideration when a nuke could glass your supply chain in one blow.

      I don’t think 5×7 is a bad round, but it doesn’t have the same user base so it will always be more limited. A ps-90 in 9mm would be alot easier to feed…

  • Jean Luc Picard

    Hehe, I see my post wasn’t unnoticed 😛 I wonder why the system hasn’t been used in assault rifles for example, because it’s practical as it keeps the profile low and it doesn’t interfere with the environment. The only downside of this is the lack of possible ways for expansion.

    • wetcorps

      It hinders the use of sights and scopes too.

      • iksnilol

        Can also be awkward to reload.

        • ostiariusalpha

          Even on a bullpup, it will always be faster and more intuitive to reload with a bottom feeding detachable magazine except in prone. Then it’s kind of a wash.

        • wetcorps

          I think it’s like bullpup and conventional layout, depends on what you trained with.

          • iksnilol

            Yeah, but look at the P90. The sights have to be far enough away to not interfere with the magazine. And you also have to reach over the gun, “extract” the magazine upwards then pull it back towards yourself. Way more awkward than pressing a mag release and pulling out the mag on an AK or AR.

    • Out of the Blue

      The biggest limitation on this, in my mind, is the length of the cartridge. A conventional caliber chambered assault rifle with this magazine system would be fat with a capital F.

  • HKmaster

    It looks like the barrel and flash hider of the hill smg prototype came straight off an MP-40

  • iksnilol

    Sorta what the P90 should have been… (HINT: 9×19).

    • Kivaari

      Yes, a real cartridge. I get reports from P90 (not “s”) owner that the magazines are fragile.

  • Mutenri

    This shows that the P90 design is perfectly transferable to a more accessible cartridge like 9mm. FN plz.

  • Southpaw89

    The appeal of such a magazine would no doubt be the way it streamlines the rifle, with nothing to snag or interfere with shooting positions. I’d like to get my hands on a rifle that using one like this just to see how well it works.

  • marathag

    Link to Volume I?

  • whoa

  • Zebra Dun

    I believe the best route for a round is like the best route for a 4 wheeler going up or down a hill.
    Straight up or straight down.
    Straight in and straight out.
    But these systems seem to work.

  • gregge

    For Volume III I nominate the Calico Arms carbine and pistol. The carbines were so weird looking that a bit of silver paint applied to some of the parts made them quick (but expensive) props for Mel Brooks “Spaceballs” movie.