W+F Bern P47 Experimental Gas-Delay Pistol

The Swiss were the first country to adopt a self-loading service pistol; the Luger in 1900. They would keep those in service clear through World War 2, at which point they began seriously looking for a more economical and more modern replacement. During the 1940s, a number of experimental designs were developed at the SIG and W+F Bern factories in hopes of becoming the new Swiss service sidearm.

This example is a P47, one of 10 guns made in 1947, at the end of W+F Bern’s developmental series. While the preceding guns had been largely based on the Browning High Power, the P47 was a gas-delayed blowback action similar to the H&K P7, Norinco 77B, and Walther CCP (although predating all of those). Its barrel had gas ports just in front of the chamber which led into a gas piston that acted to hold the slide in battery when pressurized. Thus the slide was delayed from opening until the bullet has left the muzzle and gas pressure had dropped enough for the recoil spring alone to safely control the opening of the action.

Unlike Bern’s previous experimental pistols, these 10 P47s were all identical (and have serial numbers in the low/mid 40s to low/mid 50s). I had a chance to shoot one of these (serial number 46), and it was a pleasant enough piece, although in my experience the gas delay system did not provide a substantial improvement over what was ultimately adopted by Switzerland, the SIG P210.

24 Comments

  1. I suspect that this would require the barrel and slide to be forged and machined from stainless steel. Because the P47 is a gas-delay blow-back, it stands to reason that the recoil spring must be quite stiff, even with the gas-delay. Was the P47 rather heavy for its size, Ian?

  2. Diving into the firearm history, needs counter resets about which being the first in related field. Bern P47 seems the very first in the gas brake system used in handgun sized firearms. However, with all exiting samples, this construction should be accepted as a bolt speed slower in alongside its full backward travel rather than delaying the breechbolt opening within the very limited rearward distance in which the highest pressure in the chamber occurs. Trigger Lockwork seems interesting which a single main spring powers both sear with disconnector and hammer. Two stage trigger release looks also outstanding. A pistol made through the approach of fine Swiss watch craftsmanship.

    • Agreed
      It’s the inertia of the slide that keeps the case from backing out of the chamber fast enough to burst.

      The gas pressure doesn’t get into the gas system fast enough to have a delaying effect.

      The spring and gas piston serve to slow and buffer the slide later in its travel, cushioning it’s impact on the receiver, and avoiding the need for a brutally heavy recoil spring to slow the later part of the slide’s rearward travel.

      • I’m not sure if I totally agree. It seems to me that given a sufficiently large gas port and a piston larger than the bore diameter, that you could actually drive the slide forward.

        • Even in the closest gas out holes near the chamber, like P7, system works near its limits as a shock absorber and bigger calibers over 9x19mm, pressure handled within the short barrel length, gives no ability to slow the full backward bolt travel. As a result of this happening, some HK P7 pistols of bigger caliber, had to be built with needed free blowback mass discarding the gas brake tube.

  3. “Luger in 1900. They would keep those in service clear through World War 2, at which point they began seriously looking for a more economical and more modern replacement. During the 1940s, a number of experimental designs were developed at the SIG and W+F Bern factories in hopes of becoming the new Swiss service sidearm.”
    Were Swiss firms experimenting with automatic pistols designs earlier, say for export purposes?

  4. Speaking of cool, it may be in jargon of our days, but I am sure the pistol’s thermal state was just the opposite – very hot, very quick. Are there challenges in this design part of heat? You bet. One is alignment of that little ‘piston’ with corresponding bore. Besides, it surprises me it does not contain usual semi-labyrinth.

    Well, all ideas on hand were tried and winner is Petter/ SIG.

    • “Speaking of cool, it may be in jargon of our days, but I am sure the pistol’s thermal state was just the opposite – very hot, very quick”
      Is heating up of automatic pistol really that problem? How many magazines was one user supposed to carry?

  5. Hk p7 gets hot very quickly,
    So quickly that the makers added some plastic insulation to make it more comfortable for the firer’s trigger finger.

    I don’t know whether anyone has managed to fire sufficient shots through the little jelly bean shaped vektor pistol to see whether it gets hot 😉

  6. Most successfull gas brake pistol seems Steyr GB since constructed what it should be. However, new CCP of Walther, at least using the concept, looks in a par with Steyr.

    • I’d agree with that Steyr GB, I like it too, specifically for use of precision casting. But as we know, it did not last long even in country of its origin. So we can guess on utility of gas-brake concept; not very good one, overall.

  7. In fact, Steyr GB seems one of the most sturdy service pistols ever produced but lost its advantages in favour of another Austian pistol which got introduced within the same time. It’s frame was made two halves of stamped steel plate and welded together. The trigger guard which made of plastic, inserted thereafter over the textured paint. Its construction seems rather cost saving but can not match with its plastic framed rival. For the time being, Umarex (Walther), seems the survivor of the system in pocket pistol genre and looks highly succesfull. IMHO.

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