Busting the Myth of Semi-Smokeless Swiss Ammo!

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Myths may come from many places; one of the most common sources of myths is the gap between languages. Translations, no matter how good, are imperfect, and this is especially true when concerning delicate works like poetry or technical documents.

Even translations between languages that have very well-characterized relationships, like English and German, are subject to errors, and what we’ll be taking a look at today is one such example of a questionable translation from German to English. In German-langage sources from Switzerland, the propellant used by the first generation Rubin-designed .30 caliber 7.5×53.5 GP90 round of the 1889 Schmidt-Rubin rifle is described as rauchschwach, which translates literally to “smoke weak”.

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English-speaking translators writing about the Swiss ammunition interpreted this word to mean that the GP90 round used what’s today known as “semi-smokeless” propellant, which describes a variety of propellants intermediate between blackpowder and true smokeless propellants. This semi-smokeless label has been repeated almost universally in English sources, and is now accepted as common knowledge.

However, this translation doesn’t make very much sense. Colonel Rubin, who designed the GP90 round, was by the late 1880s aware of true smokeless nitrocellulose propellants, and indeed was one of the early innovators of them. If this was the case, why in 1889 when nitrocellulose propellants had finally been perfected in multiple countries, would Rubin have settled for far less energy dense hybrid propellants? Further, the exact same term rauchschwach is used in the K11/K31 manual to describe the decidedly smokeless GP11 cartridge:

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Was the GP90 really a “semi-smokeless” cartridge? YouTuber Bloke on the Range packed up a couple of Swiss rifles and some original ammunition to settle this matter; the resulting video is embedded below:

That’s MYTH BUSTED for you folks reading along at home! The 7.5×53.5mm GP90 does not use “semi-smokeles” powder, but rather an early extruded and cut nitrocellulose variety, of the kind that has since become extremely common.

Now, a small note is in order. The ammunition Bloke is shooting is 1909-dated GP90/03, which uses a different primer than the original GP90 round. However, every other element (including the paper jacket on the bullet) is the same.



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 can be reached via email at nathaniel.f@staff.thefirearmblog.com.


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  • PK

    Original research is so helpful in situations like these. Now we all know for sure! Interesting.

    • ostiariusalpha

      Mostly. The ammo bloke is shooting is GP90/03, not the original GP90; they switched to a less corrosive primer in 1903. We can fairly safely assume that the propellant stayed the same PC88 formulation as before, but that is just an assumption, likely as it may be.

      • This is in fact mentioned at the bottom of the OP… And the 03 primer was less *erosive* rather than less *corrosive* (I need to find a source with the details, but a good first guess would be elimination of something abrasive like ground glass from the formulation).

        • ostiariusalpha

          I’ve heard nothing of glass elements in the priming compound, but Die Repetiergewehre der Schweiz says they removed the mercury from the GP90/03 primers, which is a corrosive.

          • Ken

            I believe mercury fulminate primers are noncorrosive. However, they do degrade over time much more quickly than other primers. The mercury residue from firing also attacks brass cases and makes them unsuitable for reloading, which a lot of militaries did with their peacetime training ammo.

          • ostiariusalpha

            The fulminate will also attack the brass even just during storage. That stealing of copper and zinc atoms, with fragile alloys left behind, is corrosion.

          • marathag

            Makes me wonder about the old timer method of de-leading and coppering a barrel with a cork and a flask of Mercury.

          • ostiariusalpha

            Setting aside the fact that there are safer solvents that don’t cause permanent neurological damage, mercury is pretty much the most potent de-leading agent you can use, but the same rules apply to it (only more so) as other highly effective de-leaders like Lead Out: don’t leave any of it in the barrel when you are done or it will damage the bore. For all its genuine effectiveness, it really doesn’t seem worth it for the quite serious health risks and difficulty obtaining useful amounts

  • Kovacs Jeno

    The German “rauchschwach” is a much more precise technical term for cellulose-nitrate based powders than the English “smokeless” because it is not entirely without smoke.

  • Cmex

    Honestly, smokeless powder is a somewhat relative term. Some smokeless powders make hardly none while others release a comparatively large amount. A good amount has to do with barrel length and burn rate — a more complete burn means less smoke and fire out the end. A less complete burn means more trash getting blown out the front. Regardless, it is all much less smokey than black powder.