Scotti Model X – Shooting, History, & Disassembly (Video)

The Scotti Model X (the X standing for the 10th year of the Italian Fascist era, or 1932) was one of several semiauto rifles tested by the Italian military during the late 1920s and early 1930s. The Scotti entry into these competitions was chambered for the 6.5mm Carcano cartridge and used standard 6-round clips, identical to the Carcano bolt action rifles. It also used sights basically identical to Carcano rifle sights. Where it was rather unusual was its open-bolt action, a system typically found in machine guns.

Open bolt means that when the rifle is ready to fire, the bolt is locked all the way back. Upon pulling the trigger, the bolt moves forward, picking up a cartridge, chambering it, firing it by means of a fixed firing pin, and then extracting and ejecting the spent case and locking open again, ready for another shot. This system can be used with either locked or blowback actions, and the Scotti X uses a two-lug rotating bolt to lock during firing.

In total, just about 250 Scotti Model X rifles were manufactured, and the never progressed past initial field trials. A few later models were made in very small numbers as late as 1936, but these also failed to gain any acceptance. I made some slow motion videos of this rifle a little while back, and finally took the time to do a complete video on it, including disassembly:

33 Comments

    • В.Е. Маркевич states that Scotti offered conversion to self-loader for any military repeating rifle. If I am not mistaken that rifle was made from Mauser rifle.

      However notice that this document also points that:
      Scotti produced also other weapons utilizing this principle: 9 mm automatische Pistole, (i’m not sure how it should be understand: as automatic pistol XOR sub-machine gun?), LMG for Navy, 13,2mm AA-MG, 20mm AA, 37mm AA and 40mm AA.

      Link in above don’t work as intended, to get pdf just copy whole link (from http to 968) and paste into address bar

      • The Scotti 9 x 19mm automatic pistol is shown in patent cross-section on p. 485 of Handguns of the World by Ezell. According to the diagram, it was a gas-operated system using a rotating-barrel lockup similar to the Steyr 1911, Mexican Obregon, or MAB PA-15 (which were all recoil-operated, of course).

        The system is difficult to understand from the diagram. It appears that a gas port just behind the muzzle allows gas to blow back onto the head of an operating rod (as on the Scotti X rifle), throwing it back about 5-6mm against a spring-loaded arbor that then moves backward, rotating the barrel and beginning the unlocking sequence.

        The barrel appears to be stationary except for the rotating bit. The breechblock looks as though it recoils against yet another spring behind it, acting rather like the rifle breechblock.

        There is a long coil spring around the “operating rod” (if that is in fact what it is), rather like the recoil spring in a modern Glock, H&K, etc., that seems to serve no purpose.

        The searage looks very much like the rifle setup, leading me to suspect that the pistol also fired from an “open bolt”. It has a grip safety that blocks the sear from dropping until “squeezed”, moving its upward extension forward thus clearing the sear. And the trigger guard has an exaggerated forefinger “hook” rather like some custom automatics did 20 years ago. Trigger pressure is transmitted to the sear by a transfer bar very like that on a cheap Spanish “Eibar” .25 ACP. Magazine capacity seems to have been 8 rounds in a single column; the caption states that the barrel was 100 mm long, and the pistol weighed 500 grams.

        That “trigger guard hook” bothers me. Coupled with that otherwise-seemingly-redundant spring around the operating rod, I think (SWAG) that the pistol was intended to be loaded by cycling the action by pulling back on the “hook” with the trigger finger as on the Lignose Einhand .25 pocket auto. (?)(!)

        The caption states that the pistol was “proposed”, indicating that it may never have reached the prototype stage. With such a Heath Robinson arrangement, it may have been too much for even the Italian Army ordnance department to swallow.

        cheers

        eon

  1. Some idiot would attempt to classify this as a machine gun just because of the open bolt operation. Automatic fire wouldn’t happen unless the trigger sear was made incorrectly, and besides, there is no use for a six-shot fully-automatic, right?

    • “Some idiot would attempt to classify this as a machine gun just because of the open bolt operation.”
      Who? I never see description of Scotti Model X assuming that this is machine gun.

      • The U.S. BATFE definition of “machine gun” includes any weapon using open-bolt, advanced-primer ignition firing with a fixed or semi-fixed firing pin. For example, M60 and M60A1 7.62 x 51 GPMG.

        So yes, under U.S. BATFE regulations, the Scotti X could be defined as “Any Other Destructive Device”, due to being relatively easily modified to deliver full-automatic fire.

        Of course, with only a 6-round en bloc clip, it would be a pretty short burst, given the probable cyclic rate.

        cheers

        eon

      • It’s a political comment. In America, the ATF has deigned that many semi-auto rifles with an open-bolt action are “easily converted to machine guns” and restricts them in the vein of NFA rifles.

  2. “The Scotti entry into these competitions”
    Now I’m interested in requirements of that competition? Does it allow only 6.5mm Carcano weapons? Has some limit (overall length, mass, minimal magazine capacity)?

    “Where it was rather unusual was its open-bolt action, a system typically found in machine guns.”
    I guess that it might be caused by fact that Italian Army at the time has successfully issued open-bolt sub-machine gun (Beretta OVP)

    “It also used sights basically identical to Carcano rifle sights.”
    В.Е. Маркевич states that Scotti rifle itself was conversion of Mannlicher-Carcano 1891. He gives following data:
    Mass: 4050g, rate-of-fire (practical): 40…50, fire: semi-auto only
    He also that there were some rifles for navy with stock from foam alloy (Aluminium, Magnesium, Silicium), painted in camouflage colour.

  3. It would be very difficult to fire an open bolt accurately, since there is all that mass in the bolt assembly knocking off your aim. maybe with enough practice, one could compensate for it.

    • “It would be very difficult to fire an open bolt accurately, since there is all that mass in the bolt assembly knocking off your aim. maybe with enough practice, one could compensate for it.”

      *********************

      some air rifles who have a heavy piston and spring have the same problem. there is a kick just before the bullet leave the barrel.

  4. In 1930s Italy other semi-automatic rifles were developed:
    Breda M1935 PG
    Variants
    -6.5mm Italian – semi-auto rifle – not pressed into Italian service until 1943
    -7×57 Spanish – selective (semi/4-round burst/full) for Costa Rico, about 400 examples made
    (data according to Modern Firearms site)

    Armaguerra Mod. 39
    Italian Wikipedia has query about that weapon
    https://it.wikipedia.org/wiki/Armaguerra_Mod._39
    with more info than English counterpart.
    Sadly I don’t know Italian, from description I understand (fix it if I mess anything):
    – 10000 examples were ordered from Società Anonima Revelli Manifattura Armiguerra in Genoa, hence Armaguerra (Società Anonima Revelli Manifattura Armiguerra) name
    – because Italy Army switch from 6.5x52mm Italian to 7.35x51mm Carcano this gun has to be redesigned, this lead to some problems and new version enter production in 1943
    – short-recoil operated
    – compatible with 6-round clip for Carcano Mod. 91/38
    – compatible with bayonet for Fucile Mod. 91 and with bayonet for Carcano Mod. 91/38

    So apparently if Italian Army don’t switch for new infantry cartridge (7.35x51mm Carcano) it could produced more Armaguerra Mod. 39 than in real-time-line.

    Can you explain me why Italy switched from 6.5x52mm to 7.35x51mm? Does that later offer much better performance from rifle? (In machine guns Italians used 8×59 Breda cartridge) If poor performance was caused by blunt-nosed bullet why not redesign bullet instead of whole cartridge? (For example 6.5×55 Swedish has initially round-nose bullet but later get spitzer bullet)

    • Often the view is that the Italians chose 7.35 mm because they could use worn out 6.5 mm barrels and re-rifle them to the new calibre. I talked to several people experienced in making barrels, and none of them thought this approach more economical than making new barrels from scratch and scrapping the old ones. The rough surface and irregular diameter changes are a nightmare for starting a new quality rifling (in a high volume industrial environment).

      I do not know why they did it, but interestingly, nearly all “6.5 mm armies” kept the round nose bullets until the end. Only Japan (already 1905) and Sweden (as late as 1941) generally introduced spitzer versions. And after WW1 practically all introduced powerful machine gun calibres about 8 mm (Netherlands converting the Schwarzloses from 6.5 to a rimmed 7.9 for example).

      My personal view is that choosing 7.35 mm was mostly a response to recognizing the limited range of rifle shooting in combat, at the same time enhancing wounding power and reducing recoil. The bullet shape is halfway between round nose and spitzer, and it has an aluminium tip in the core, similar to British Mk VII.

      • There are two stories about the change to 7.35mm.

        1. The Italian Army was dissatisfied with the lethality of the 6.5 x 52 round in Africa and in WW1 vs. Austria, and developed the 7.35 x 51 round as a result. I find this unlikely, first of all because the 7.35 x 51 was only developed in the 1932-34 time frame, and second because the 6.5 x 52 has ballistics close to those of the 6.5 x 53R Dutch & Romanian Mannlicher, which makes it actually a bit more powerful than the 7.35, which is closer to the American .30-30 Winchester Center Fire in velocity and energy.

        2. The Italian Air Force wanted a round with a bigger-diameter bullet to allow for better armor-piercing performance and the ability to use tracer and incendiary tracer ammunition. I find this more likely because even today, fitting tracer comp, especially incendiary, into a bullet much below 7mm diameter can be a bit of a technical challenge.

        It’s noteworthy that the Air Force got 7.35mm machine guns for their planes first, made by Fiat and Breda. Army procurement of 7.35mm chambered rifles (new production, including new barrels) lagged behind MG procurement, and as such the Italian Army was stuck with two different “standard” rifle calibers when they got into the war.

        Not to mention three different MG calibers; 6.5 x 52, 7.35 x 51, and 8 x 59 in the Breda Mo.37 heavy MG, apparently the only weapon ever to use that specific cartridge other than the older Fiat-Revelli M14/32.

        Plus three “standard” pistol calibers; 7.65 Browning (.32 ACP), 9mm Corto Browning (.380 ACP), and 9 x 19mm Glisenti; same cartridge case as 9 x 19mm Parabellum, but operating at pressures closer to .38 Special revolver- 9mm P would probably blow up a Glisenti or Brixia retarded-blowback, or Beretta M1912 “straight” blowback pistol.

        And oh yes, the Beretta M38 SMG used a super-powered version of 9 x 19 equivalent to the 1980s Israeli “Uzi Carbine” load. The later German 480D code 9mm for the MP-40 was similar in range, wallop and pressure, both were “+P+” by modern standards. Either of these darned well would blow up any of the pistols. (NB; late-1942 photos show at least some Italian and German troops equipped with the Beretta M38 having Polish Vis.35 or FN P.35 “Pistole 640B” 9mm handguns.)

        IOW, in 1941 or thereabouts, an Italian Army infantry section with 20 men, two MGs (one light, one heavy), two or three SMGS, several rifles, and a junior officer and an NCO with pistols, could have up to six or seven different cartridges needed within the section.

        You have to feel sorry for the Italian Army’s quartermasters.

        cheers

        eon

        • Pity that the Fiat 35 was worse than the original Fiat-Revelli Model 14 in that it easily overheated and was chambered for a special round only shared with the Breda 37.

          • When they wanted a better rifle round, they could have just used the 8 x 59 Breda.

            According to Barnes, the known loads were a 210-gr. at 2600 for 3160 FPE, and another one of unknown bullet weight at 2952 F/S, probably around 165-gr., which would have yielded about 3190. IOW, ballistically and most other ways pretty close to the American 8mm-06 wildcat of the immediate postwar period, or the older German 8 x 64(S) Brenneke sporting round.

            In fact, you could argue that the 8 x 59 Breda was really more of a big-game sporting round than a military type.

            Of course, to use it safely they’d have needed a rifle with a stronger action than the Mannlicher-Carcano. I’d have gone with the Mauser 98 action.

            And ensure that it was well-rubbered at the butt, as Lord John Roxton would say.

            cheers

            eon

          • Okay, so if the Italians had gone with heavy Mauser rifles chambered for 8 x 59 Breda and machine guns to match along with competent commanders, how would they have done in hypothetical infantry battles against the Russians? Yes, Italian troops did get sent to the Eastern Front… And they likely got dominated.

          • “Of course, to use it safely they’d have needed a rifle with a stronger action than the Mannlicher-Carcano. I’d have gone with the Mauser 98 action.”
            P.O.Ackley tested Carcano for strength and it proved to be strong:
            http://forums.gunboards.com/archive/index.php/t-3529.html
            I am not sure about original Carcano ability to chamber 8×59, but after some redesign it should can handle 8×59 Breda

            “Mauser 98 action”
            Sweden used Gevar m/40 which was Mauser 98 action chambered for 8×63 patron m/32 (Swedish cartridge for machine gun)

        • “2. The Italian Air Force wanted a round with a bigger-diameter bullet to allow for better armor-piercing performance and the ability to use tracer and incendiary tracer ammunition. I find this more likely because even today, fitting tracer comp, especially incendiary, into a bullet much below 7mm diameter can be a bit of a technical challenge.”
          Ok, but why not get ready 8×59 Breda?

          • You tell me, and we’ll both know. I could almost understand not adopting it as an infantry rifle caliber, because with ballistics close to some of the .30 cal. British Express rounds, it would have a pretty serious kick, especially for troops used to the lighter recoil of the 6.5. (I use a 6.5 x 55 Mauser, and my rheumatoid arthritis appreciates it not kicking like a 7.9 x 57.)

            But in an aircraft fixed MG, where recoil isn’t an issue and you want as much velocity as you can get plus a bullet big enough to make a good incendiary tracer round, the 8 x 59 would seem to be the ideal solution short of a full-on 12.7mm “fifty”. (Which the Italian AF actually had after 1939, a Fiat-made copy of the Browning M2.)

            In the Western Desert, the British used all the Breda M37s they could “acquire”, because it had more range, better accuracy, and more punch than their own 0.303in MGs. And even with its Hotchkiss-type metal strip feed (that oddly returned the empty to the strip rather than ejecting it- ?), it was still a very reliable feeder, even in dirty and sandy conditions.

            If they could have come up with a version of the Breda M37 with a belt feed (belt pull might have been an issue), they would probably have had about the second-best rifle-caliber aircraft MG in the world. (I maintain that the Browning in .30-06 was the best overall.)

            Considering that they were part of the “opfor” before ’43, maybe it’s just as well that they didn’t.

            cheers

            eon

      • “Italians chose 7.35 mm because they could use worn out 6.5 mm barrels and re-rifle them to the new calibre”
        I doubt it that, just see pressures for both:
        http://kwk.us/pressures.html
        6.5mm Italian gives 41000 psi (CIP, piezo)

        7.35×51mm Carcano query in en wikipedia:
        7.35mm Carcano gives 51000 psi (?, ?)

        If you re-bore barrel from 6.5mm to 7.35mm it would have thinner walls, steel is still the same so UTS (ultimate tensile strength) remain same;
        If rifle barrel is steel tube therefore BARLOW’S FORMULA can be applied, if:
        -pressure is higher
        -UTS same
        -outside diameter same
        -wall thickness is lower
        it must lead to lower safety factor, so whoever decided to reuse old 6.5mm barrels must accept that

  5. Wonder why there should be extracting problem. Those locking lugs are slanted and this is suggesting prime extraction is used in this design. Neat design overall – compact operating mechanism for sure.

    Shame the forward momentum is not used to counter recoil force.

    • I think it is, at least partly. If the bolt were fully “at rest” when the round fires, I’d expect it to be much heavier and have a more powerful recoil/firing spring. So I’m guessing (SWAG) that there’s at least some degree of advanced primer ignition, with the bolt body still moving forward as the bolt head is rotating into final lockup, as the firing pin sets off the primer.

      So the recoil force still has to arrest at least some forward momentum of the bolt body and spring before the recoil stroke can begin. Also the bolt head’s rotational inertia turning into lockup has to be stopped and reversed, camming it back out of lockup. This also uses up recoil kinetic energy before the bolt body begins moving backward again.

      Still, the slow-motion video shows smoke and what look like “sparks” from the chamber as extraction and ejection take place. This strongly indicates that the bolt is opening with fairly high residual pressure in the chamber. A characteristic it would share with several Italian machine gun designs, all of which needed lubricated cartridges to avoid case-head separations.

      To work consistently, the Scotti would require ammunition made to much tighter tolerances of bullet weight, muzzle velocity, powder burning curve, etc., than Italian industry was capable of delivering at that time. For that matter, I doubt the 1943-44 Lake City contract lot of 6.5 x 52 for the Italian Co-Belligerent Forces was made to tolerances tight enough for the Scotti to be happy working with it. Even with lubricated cartridges.

      The Scotti design may fall into the “Just too precious to work consistently” category.

      cheers

      eon

      • Sorry, I think your physics is wonky there.

        By the time the bullet has reached the gas port and the gas piston has started to react, the bolt carrier is certainly at rest (or has even bounced).

        I suspect that there is little or no mechanical leverage for primary extraction, and that the camming surfaces just turn the bolt head as it moves back being pulled by the carrier.

        What I suspect is happening is that the chamber is not well finished and thus puts up a bit much friction. Since there’s sparks coming from the chamber on ejection, it looks like there’s still a bit of residual pressure that hasn’t had time to dissipate, and thus the brass is still tight in the chamber, “gripping” it, since it hasn’t had time to relax and come away from the wall. And why the extractor was slipping over the rim. And which is why it works with enough lube in there.

        Typical Italian firearm design problem – lack of mechanical advantage for primary extraction and trying to extract too early. Although mechanical advantage is not strictly necessary if everything else is well made – AR15’s have none, for instance, and nor do M1 Garands or FAL’s, amongst others.

        What is impressive about the piece though is its simplicity compared to many Italian designs. I see what he was going for there, and I think the open bolt decision was taken just to keep it simple, thus avoiding lots of parts in the fire control area.

        • I read both eon’s and your own comment and appreciate both. In my view you have both valid observations while maybe interpretation is slightly different.

          I’d suggest to look again at “sparks flying out of chamber”, this to me is suggestion that the gas piston function is secondary and merely “confirms” that breech gets open. Most of doing is right at locking lugs geometry. If that is the case, this is a transition locking concept with some effect of bolt forward inertia.

          So, in my humble conclusion this is likely another attempt to overly complicated and fuzzy Italian design. At this point we all are likely to agree.

  6. A fascinating presentation, thank you.
    What surprises me is that the Italians have here the rudiments of an efficient light machine gun. Beef up the works, give it a quick-change barrel, and a proper magazine feed (from the left for example). Instead they went ahead with the awful Breda 30, with its much-too-short barrel, its lousy extraction, weird magazine that has to be clip-fed, and oiled cartridges. Somehow there seems to have been a lack of coordinated effort.

  7. So the locking lugs are slanted on their rear faces. Does that mean they mate with slanted faces in the receiver? If so, then it seems that it might act as a Blish lock. I’d like to see if the bolt still reciprocates if the operating rod is removed.

    • A distinct possibility. Being rather familiar (several years’ worth) with the M1921 and M1928 Thompson, I’d expect that the locking lugs and recesses would probably require careful lubrication, neither too much or too little. (In my experience, the Blish “H” piece is happiest with modern liquid Teflon lubricants like Rem Dri-Lube; failing that, graphite. Oil tends to make it sticky in cold weather.)

      If so, this would put the Scotti in the category of a gas-unlocked hesitation-locking system, almost but not quite a retarded blowback.

      While rare, it isn’t entirely unknown; the Mannlicher Model 1893 semiautomatic rifle was such a hesitation-locked system, and was noted for opening with high residual pressure in the chamber.

      Scotti may have been trying to use the gas-actuated unlocking system plus the forward inertia of the bolt to increase the dwell time of the unlocking sequence to reduce the chances of a blown case.

      It occurs to me that while it’s a bit too persnickety to work in a rifle of reasonable weight (mainly due to needing more bolt mass than it has), as a machine gun action it would probably be a bit simpler than either a “straight” gas-operated weapon (like the Bren or BAR) or a “straight” recoil-operated locked-breech weapon (the Brownings and Vickers-Maxims, etc.).

      Given a quick-change barrel, a decent belt-feed, and a bipod, it might have been the SAW the Italian Army needed and never had. Note that postwar, they adopted the MG42/59 (German MG-42) in 7.62 x 51 over all the alternatives, including American ones.

      No fools, they.

      cheers

      eon

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