SIG PE-57: Swiss Roller-Delay! (Video)

The SIG PE-57 is the civilian semiauto version of the Stgw57, Switzerland’s first self-loading service rifle. Developed from the German MG-42 but incorporating a substantial influence form the FG-42 as well, the PE-57 is a roller-delayed blowback action chambered for the 7.5x55mm Swiss cartridge. It was also made for US commercial expoert as the SIG AMT (American Match Target), and sold to the militaries of Bolivia and Chile.

The PE-57 uses an in-line stock layout much like the FG-42, which minimizes muzzle climb, as well as a folding bipod which can be positioned at either the front or rear of the barrel shroud. The standard magazines hold 24 rounds. This rifle looks very awkward, but handles quite well, except for its rather heavy weight (12.25 pounds / 5.6kg). It is most at home in a fixed position, firing at long range targets from its bipod.

Only a few thousand of these rifles were ever imported into the US, and I would like to thank Bob for generously providing use of this one for video!


  1. I imagine that the PE-57 was intended for shooting range use and other tasks like hunting or police standoff marksmanship. But then of course it’s likely useless for fending off house robbers (military grade 7.5×55 mm Swiss is freakishly expensive and overkill inside the house). Did I mess up?

    • Why would the cost of self defense ammo really be a concern? The idea that the cost of ammo matters when it comes to self defense is common among delusional anti-gun pols..i.e. taxes on ammo to stop homicides…but of course is designed only to harm target shooters and collectors. Whether a mag full of 9mm costs $ 7.50 or 15 bucks is irrelevant if you carry it for defense or intimidation.

      As to “overkill” there may be such a thing but not until you need a tripod or wheels to hold the gun.

    • “fending off house robbers (military grade 7.5×55 mm Swiss is freakishly expensive and overkill inside the house)”
      But this was NOT objective of designers of this weapon. It is military fire-arm designed for firing default (at that time) cartridge of its intended user.

      What if enemy use body armor?

  2. Greatings from Italy, Ian.
    Long time lurker, recent patreon: thanks for your work!

    I’ve been shooting and partecipating for some years in Switzerland in small competitions, with PE57s and PE90s. Some curiosities I’ve learned along the way regarding this great, and VERY accurate rifle:
    – The rear sight’s dial of swiss PEs/Stgws shows two notches labeled with a “3”, one white and the other one red: they are used to sight in at 300m on the standard swiss paper target, aiming at its wider 1 point white circle (the former) or the smaller inner 5 points black circle (the latter). The white 3 gets more used for field training/full/3 round burst fire, while the red 3 is generally used for single shot and in competitions/yearly shooting qualifications (Swiss Army) which take place at that distance.
    The 3 round burst is so taught: aiming with the first round for the right thigh, then guide the follow up shots along the recoil line to che chest (heart) area and neck/head. That’s in order to maximize the probability the kill/incapacitate the opponent.
    – The white tag on the right side has a purpose! It denotes a gun that is semi auto. On the standard Stgw it is reversible (the other side is black): that’s because as swiss militiamen can purchase their rifle at the end of their active service, so their rifles need to be converted to semi auto only (Stgw.58P – Privatizzato/Privatisiert/Privatisée). It helps visually identifing them when stored, or at the ranges.
    -The bipod. It is almost generally used deployed at the front. The rear position is mostly used whith 30 round mags in prone position, or with rifle grenades (in fact, in the Stgw it is graduated along its legs to help aiming it).
    As shown in your companion video on InRangeTv (keep up with the good work!), it does have some deficiencies and tends to swing around: in fact a good number of (if not all) Swiss Federal Ranges have (or used to have) a small shallow duct build parallel to the prone shooting stands where to extend its feet in(and also helped lining up the rifles in order not to damage the microphones of the Polytronic scoring systems…).
    – In order to fire grenades, it uses a dedicated magazine:
    – There’s one more official variant, to the ones you mentioned the 510-7T
    – Its cleaning kit is superb! It works wonderfully not only with 7.55×55 rifles, but also with any .308 one.
    – Its bayonet, like any swiss bayonet (beside the one for the Stgw.90)is pointy but not that sharp .
    – Here’s a link to a cutaway model:
    Actually they still keep popping out at Lausanne and Luzern gun shows, along with prototypes.
    – Beretta is rumored to have produced if not entire guns, quite a number of spare parts, to circumvent SIG’s export limitations.
    – It has been issued to Vatican’s Swiss guards as well (its members used to have to bring their weapons with them).

    In your video with Karl, comparing the Stgw.57 to the G3 family, you mention that Switzerland has managed to arm itself with expensive guns like this one being a country with a small population. It’s not only that: the ratio number of soldiers /total population, till the ’90s, used to be one of the highest in the world. It is a rich country, but doesn’t have to spend on a Navy, while its Air Force (which is branch of the Army) gets a fraction of the budget. Things started to change first during thr ’70s, when high tech systems had to be purchased (especially for air defense) along with massive investements needed to implement the public NBC civil defense (its nuclear shelters were probably the most expensive defense infrastructures in western Europe since the Maginot Line).

    I hope you’re having a great time travelling Europe!

    • Hello Lorenzo

      Sorry to qualify a couple of your statements above.
      There is absolutely no 3round burst with the Stge 57. As for the sights: The ‘red 2’ is the battlesight used in the field, the white markings are for precision shooting either on the range or in the field.
      I too see the bipod used in the forward position on the range more and more. But this is not ‘according to the book’. The Reglement clearly says single shot from the rear position only, NEVER the forward position which is used for automatic fire only..You shoot the rifle usually (and on the 300 m range exclusively) in prone position.
      There are 2 ways to shoot rifle grenades with the Stge57: Either ballistically, using one of the bipods for range indication with a pendulum (usually the Swiss Army knife on a string) attached to the bajonett lug, buttstock firmly anchored on the ground. Or anti tank grenades with a flat trajectory, holding the butt of the rifle under your armpit (NOT on the shoulder!) and fire the grenade which kicks viciously. Doing it from the bipod wold probably break your shoulder and your aim would be absolutely nil. The special magazine for the special rounds is an adaptation of the K31 magazine. Battle drill is: Put the rifle on safe, remove the magazine, pull the bolt to eject the cartridge in the chamber, put the withe magazine in, pull the bolt to insert a cartridge, put the grenade on the muzzle, put the safety on single shot, fire the grenade. The rifle is not self loading when using the special round, but needs to cycled by hand.
      I do not think it ‘swings around’ if used properly ( I shot maybe 20’000 rounds with the rifle, having been in the Swiss military (Panzergrenadier) from the mid 70is until the end of the 80is)i. It is wonderfully controllable either in single shot or automatic.
      I have incidentally never seen a 30 round mag on a Stgw 57, they are always 24 round mags.
      The bayonet would have been sharpened at a mobilisation for whatever use it might have been – we used it for opening food cans etc.
      The Vatican guard (they are not only armed with halberd) used the Stgw 57 (every member of the guard has to be a trained soldier) more for shooting competitions, and of course they brought their own military issue rifle. Btw: every Swiss soldier even today gets his rifle at the first day of the basic training as a sign of thrust.
      I know, it’s quite a strange country sometimes not easy to understand by foreigners. And far too many myths abound about the Swiss military.
      Kind regards. Peter

  3. What? No mention of the CETME’s roller delay action?

    Weren’t the Sturmgewehr 44, et al, also roller delay?

    Very cool rifle nonetheless! It truly is the best of its type!

    • Wrong! The sturmgewehr 44 was gas-operated with a tilting bolt for locking. Gas pressure would force the bolt out of the locking recess and then the bolt would be kicked into the open position by the operating rod. After the spent case was ejected the recoil spring would shove the bolt back into battery with a fresh round. Did I mess up?

      • It was just a simple question based on a lack of knowledge of the German Sturmgewehr, and its similarities to the Spanish CETME (at least, in outward appearances, i.e. the single pin holding the stock and fire control group in the Stg, versus the CETME’s two pins).

        My apologies for putting two and two together and getting it wrong.

    • “Sturmgewehr 44, et al, also roller delay?”
      There was StG 45(M) roller-delayed prototype, but StG 44 as noted above was not roller delay – it belongs to gas-operated group not delay group.

  4. Hey Ian,
    thank you very mutch for this great video. Reminds me of the gun shop where i used to work back in the days. Off-the-shooting-season we cleaned, inspected and sporterized ( mounting target sights ) dozens of this guns. You mentioned the tool in the cleaning kit with wich you can lock the loaded chamber indicator when cleaning the barrel. You could actually use the tritium rearsight for that. The tritium night sight was hidden in the pistol grip and could be put on the rear sight when needed. The night sight on the front is integrated in the front sight. On the army version you have a scale on the bipod. Take a piece of line/rope. Fix one end to the bajonet-lug, fix on the other end your issued swiss army pocket knife. Put the rifle stock on the ground and now you can use the line to index the distance you want to shoot your rifle grenades ( like a mortar )on the bipod scale. Thank you very mutch for your work! All the best from switzerland.

  5. We NEVER EVER shot the select fire Stge 57 (always called ‘ Sturmgewehr’ only) in single shot with the bipod forward, either in the field nor on the 300m range. Bipod forward was only allowed in full auto – the then current doctrine was to use short bursts from up to 600 down to 300 m and single shot below 300m – as quite everybody would have been an expert shot, awesome and accurate firepower indeed.. I would like to mention the white square in the trigger assembly. This was in the select fire rifle to change the rifle from single shot only to select fire – you pulled it out, reversed it and put it back again – on white it prevented the selector switch to go to full auto. Woe to you if you entered a range house with the ‘square ‘on black’ instead of ‘on white’! You never did that twice. Uniquely Swiss was, that you took your rifle home after your yearly military service, together with 24 rounds of ammunition in a tin can, which of course you would be only allowed to open in case of a mobilisation to fight straight from your doorsteps. We always changed this little square from white to black at the start of the military service and changed it back to white at the end, so you never had a select fire rifle in civilian use. At the very end of your service you could actually keep the rifle if you wanted to, this little square was then just welded on ‘white’, later the trigger assembly was changed in order to prevent an easy conversion back to select fire. As for the quality: I fired about 20’000 rounds through my gun, quite a lot of it in full auto. The barrel was still excellent, headspace not much of a problem. I fired it sometimes ’til the barrel was red, let it cool in the snow and fired again. No problem.
    The little compartment in the handgrip Ian mentioned was not actually a cleaning kit (this came separate), but contained 3 littl plastic ‘bottles’ of fat and a rag. The Reglement stipulated that you used one of these after five magazines: take the bolt out, clean it with the rag and oil it lightly with the fat.
    The winter trigger was actually more used to fire rifle grenades – especially the anti tank grenades, which had an almighty kick. I’ve seen broken thumbs by people gripping the hand grip for that. To fire rifle grenades you had to use a ‘white’ magazine (adapted K31 mags) with special rounds.
    The load of a soldier back then was a full mag in the rifle, 6 rifle mags and 2 grenade mags on you. Quite a load, a full mag weihting 2 pounds (960 grams).
    As Ian said an absolute beauty to shoot – fortunately we never had to prove its battleworthiness, but I think this rifle would not have let us down. Thanks for the video Ian, got me some happy memories.

    • “This was in the select fire rifle to change the rifle from single shot only to select fire – you pulled it out, reversed it and put it back again – on white it prevented the selector switch to go to full auto.”
      It looks for me that:
      -it is slower than in other selective fire-arm
      -it might be lost, in worst moment
      I am wrong or not?

      • It is not to select the firing mode, but just to prevent the selector switch to go full auto. In military service it was always set on ‘black, (select fire) – as said, you changed it only at the start of the annual 3 week military service. And back again when finished. But this rifle was also very heavily used for target shooting too. And it would not do to accidentally go full auto on a 300 m rifle range accidentally, would it – so this ‘white’ setting’ was a safety measure as well, because it was visible from afar. On certain occasions there where more than 100’000 people shooting their 300m program on ranges all over the country in one day, so you had to really make sure.
        And no, I never heard of or saw the thing being lost, impossible really, because it’s a part of the trigger assembly and held in place by the receiver when the rifle is assembled.
        An by the way. Notwithstanding the fact that we took our rifles home – there were probably half a million rifles including ammunition around – there were hardly any crimes committed with it.

  6. The BATF still considers a select fire stg 57 converted into a semi auto only a machinegun, because it once was select fire?

  7. and thanks for the video. one of my all time favorites, because it is so completely different from other rifles. nice job Ian!

  8. The MG53 and the stg57 were developed from the late-war MG42V not the MG42 that
    uses a wheelbarrow type of locking roller

  9. Gents,
    there is no delay (shoot now, bolt starts later) in the bolt movement of the Stgw 57 or the HK weapons. The bolt starts moving backwards simultaneously with the bullet starting its forward motion. Same as in as simple blowback.
    What is done is slowing down the movement of the bolt-head supporting the case to manageable levels. The case moves while the bullet is in the barrel, but much slower, comparable to a simple blowback bolt of around 25 lbs.
    John Douglas Pedersens rifle achieved the same by very smart design of a toggle action. Instead of a fluted chamber he used a waxed case.
    The important thing is to be aware that bolt and bullet start moving at the same time.

  10. STG 57 are quite popular here on Belgium ranges. Most are military guns released to civilian with a replacement semi-auto trigger pack and often a new barrel.

    A quite common modification is replacing the pistol grip with one from a STG 90 (SIG 550) to make it more comfortable.
    Another mod is replacing the beer keg charging handle with a hooked one styled after the Bren LMG.
    Some entreprising people also make shorty rifles. A friend of mine shortened both the barrel and the stock of his. Recoil spring needed some tweaking but now it runs fine.

    By the way, GP11 ammo in packed in 10 rounds boxes not 12 ! 6 boxes are grouped in a 60 rounds packet. This 10 rounds box is weird as all Swiss 7.5×55 magazines are multiple of 6.

    • Yup, total hot-dog/hot-dog-bun situation there, which I still don’t quite understand. I do like the 24rnd mag, which is more than “just” 20 but not as huge as a 30 would be. Ian didn’t go enough into just how ridiculously nice these mags are.

  11. That ring in the chamber thing going on got me a thinking, what if you had a chamber specifically designed to let the brass fire form into, and grip the chamber walls, to achieve some kind of delayed blowback ?

    • “brass fire form into, and grip the chamber walls, to achieve some kind of delayed blowback”
      If I am not mistaken brass-elastic-delay (I will not hesitate if anyone supply better term) was used in:
      -Mann .25 automatic pistol, firing .25 Auto (6,35 mm Browning) cartridge – – which allow to construct small and light automatic pistol, even for .25 automatic pistols standards.
      -Kimball Arms .30 Carbine automatic pistol – .30 Carbine should be understand as cartridge name, not weapon name

        • I would forgot about ПММ automatic pistol:

          which is (as name implies) is modernized Makarov pistol, it has grooves in chamber (see description in link) to allow use of more powerful version of 9×18 cartridge. It must be noted that at that time there were several attempts to make improved Makarov pistol, varying in deep, from were shallow one, as ОЦ-35 to very deep one, being rather Makarov inspired than modification like МР-448 Скиф and its compact version МР-448С Скиф-мини, which were designed to use more modern production methods. Lack of military demand after Fall of Soviet Union lead also to development of Байкал-442 automatic sporting pistol (with regulated sights), different trigger guard (better suited for 2-hand grip) and magazine for 8, 10 or 12 round (depending on variant). Grooves in chamber for delay were also used in ИЖ-70—400 derivative of Makarov, designed to fire 9×19 cartridge, additionally slide has 30g greater mass and disassembly was impossible when magazine in weapon.

          • USPatent 1165621 Of C.A.Nelson’s of year of 1813 which took place in the
            comments of Savage.25″ pistol, describes a delay application using chamber grooves.

    • The low automatic firing rate has this rifle got, should have been precluded the necessity of providing an additional device to stop the carrier bouncing like G3 or AKM rifles.

      • That, and the fact that chamber ring *is* the anti-bounce. Rather than delay extraction by forming brass into it under pressure as said in the video, the ring swages the unfired brass as it is chambered (I built a PE57 with original barrel; unfired extracted brass is swaged) and cushions the impact of the returning carrier in so doing, as well as forcing the rollers out aggressively into tye recesses, since there is no obnoxious HK pawl spring on these guns. The downside is you can’t gently let a bolt down unless you pre-swaged the round in the chamber.

        It’s one of the reasons the gun is so soft shooting (that and the dual-stage recoil spring and long travel distance)

  12. Ejector and extractor terms are mostly confused by some but this is not valid for this rifle. There is only one piece functioning as both.

  13. Gotta love the Swiss approach to fairly simple problems… Or functions- Cuckoo, cuckoo! “A bird!” and what a bird, love it.

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