Sig’s Roller-Delay Blowback – Overcomplicated Swiss Brilliance

What do you get when you combine German inspiration with Swiss design and machining? An arguably overcomplicated, yet completely brilliant design. Designed after the Second World War, the Sturmgewher 57 is a roller-delayed blowback design with some rather interesting design items.

Unlike weapons before it, the STG-57 (and its civilian-oriented cousin, the PE-57) features an in-line stock, which helps with controlling the recoil. Chambered in 7.5 Swiss and .308 for us ‘Mericans, the weapon uses roller-delayed blowback to operate, but interestingly is over-built. As Ian at Forgotten Weapons shows, the parts are beefy, designed with battle rifle calibers in mind.

Perhaps most notable on the firearm is the significantly different extractor and ejector assembly. Rather than having two separate parts (as is most common), the weapon uses a single assembly. It a brilliant little design, with significant material to both handle the rough extraction of a roller-delayed blowback and the ejection cycle. It uses an articulating pivot to sweep the rear of the brass off the bolt face rather than rotate it out of the action. In slow-motion, this makes ejection seem opposite to all of us used to the AR and AK platforms. Combined with the unusual hammer assembly, folding sights, and movable bipod, its an uncanny design.

Ian puts the weapon through its paces with the usual full strip and breakdown. This one is a do not miss for anyone appreciating weapons design.


Nathan S

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

The above post is my opinion and does not reflect the views of any company or organization.


  • M1911

    A friend of mine has one of these rifles. The workmanship is fabulous. The rear sight looks like it was made by a watchmaker.

  • Ark

    Ermagerd I would kill for one of those.

    Though, the really brilliant video is the mud test.

  • EdgyTrumpet

    Video @15:40: Flute the chamber to make extraction easier, add a ring to make it harder. SWISS ENGINEERING

    • The_Champ

      Haha yes this does leave a person scratching their head.

  • Wolfgar

    This is the first I have heard of the chamber ring to delay extraction. Very nice!

  • Swissguy

    Thank God i live in Switzerland and can buy a used one for 300 Bucks.

    • derpmaster

      I hope they open up imports here in the US so we can get these.

    • Clint

      I’ve got one. Would love to get spare parts for it. You know, just in case. Have never been able to find an original scope mount or scope. Know how or where in your neck of the woods?

    • Jared A. Faber

      Go jump off a cliff; I hear your country is full of them.

  • Giolli Joker

    I want one now.

  • Rnasser Rnasser

    Who needs a fugly, overcomplicated 12.6 lbs rifle?

    • Just say’n

      I’ll take TWO!

      (they’ll look great next to my K-31s)

    • Vitor Roma

      I wouldn’t call it overcomplicated. Delayed blowback is a quite simple system by itself. I’d say it’s more like a very detailed rifle.

    • Herp

      I have a FNAR and I love it.

  • Seth Hill

    Another gun that needs to have versions built in US. I’m thinking with a 16″ or 18″ barrel and a longer handguard.

  • Anonymoose

    So innovative, so ugly…

  • Vermin__Supreme

    The one gun I dream about…

  • 22winmag


  • noob

    I’m interested in the weird extractor/ejector which kicks out the case base first.

    It seems like a smart idea – since the CG of the fired case will be closer to the base than the neck.

  • UCSPanther

    The PE 57 and SIG 510 are pretty ugly looking contraptions when compared with the more sleek looking 540 and 550 series.

  • Sid Collins

    Rifle PT would be a bleep.

  • RocketScientist

    Anyona have any idea if/where any of these are for sale in the states? I was familiar with the Stg.57, but this is the first I’ve heard of the civvy PE-57. I love the lines and the mechanics of the gun, and am a big fan of the 7.5 Swiss cartridge, and I feel like must now own one. This would make a great addition to my collection of straight-pull swiss rifles (and a great way to use up some the cases of GP11 I’ve got stashed away).

    • Just say’n

      There’s a .308 AMT on GB right now, $4k.

  • Fabian

    I’m a Swiss army infantry lieutenant. To get there in the early 80’s you had to go through 17 months and an half of boot camp. We shoot about 10,000 bullets and several hundred of what was called Uebung’s grenaden (UG). UG where propelled with a special cartridge. This grenade carried about 350 grams of TNT. Two kinds, anti personnel and anti tank. The anti tank was shot in direct fire at a distance of up to 130 yards. The recoil was 90 Kg, ca 200 pounds. A wrong hand position would brake your wrist.
    We also use the rifle as a ladder in house to house combat. Two guys would hold a rifle a each side and a third would step on it and the two guys would launch the third guy through the window frame.
    Then later on you’d have to go to reserve courses 3 weeks each year and mandatory shooting once a year.
    12 years later, you’d still be expected to hit bull’s eyes with your rifle at 300 meters and you would if you are into that.
    The inconvenient; the weight. With a 5 24-bullet steel magazine dotation you’d easily carry 25 pounds just for rifle, 20 hours a day. I makes for great legs and UFC fighter arms but in modern combat that would have been waay to heavy.