The Sten Gun

Discussion in 'Weapons, Technology & Equipment' started by Jet_Black_Dan, Apr 26, 2005.

  1. Don Juan

    Don Juan Well-Known Member

    From what we have gathered on this thread it seems that there were three basic issues with the Sten:

    1) The tendency to discharge when dropped or bumped.

    From what I can tell, this was possible on the Mk.II and Mk.III Sten when the bolt was forwards and the butt of the gun received a shock. The cure appears to have been a field modification in which the safety device of the Mk.V was added to the Mk.II and Mk.III. This was certainly done in Normandy, although we don’t know in detail what this modification was, or whether it was 100% successful.

    2) The tendency to run away.

    This was caused by certain early batches of ammunition, and the cure was improved ammunition. However, we have no reports that indicate that this was an issue on active service, and we have evidence asserting that it was cured before D-Day. Again, we don’t absolutely know if the improved ammunition was a 100% cure, as there may be later reports in existence that indicate otherwise.

    3) The tendency to jam

    This appears to have mainly been due to the design of magazine, which was double column/single feed and copied from the Germans. This tendency to jam was enhanced by a) ambient dust, and b) poor quality magazine springs. The Germans appear to have had exactly the same problems with jamming and ambient dust on the MP 40, although I don’t know if they had the same issues with the magazine springs. The article on Wikipedia on the MP 40 puts a brave face on things, but it is clear that it had broadly the same issues as the Sten:
    The openings in the Sten’s body for ejection and for the travel of the cocking handle also permitted dust ingress, but again these don’t seem to be significantly larger than their equivalents in the MP 40.

    While the Thompson was definitely superior in this regard, having a double column/dual feed magazine, I can’t see any obvious reason why, given adequate ammunition, the Sten would be any less reliable than an MP 40.
    Tricky Dicky likes this.
  2. Dave55

    Dave55 Atlanta, USA Patron

    They must have told the Americans the same thing.

    When my dad saw us playing with our toy Tommy guns he said we shouldn't hold them by the magazines because it would cause jams. :)

    Vic Morrow never does either.
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  3. idler

    idler GeneralList

    Perhaps the best measure of the Sten is the Sterling? The magazine is the most obvious improvement but were there any other improvements in the latter's mechanism that point to deficiencies in the former?
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  4. Don Juan

    Don Juan Well-Known Member

    The Sterling had a double column/dual feed mechanism, which according to the video below was the main improvement. A couple of interesting comments made here are that i) the magazine is the key component of any sub-machine gun, and ii) the Sterling had the best magazine design of them all.

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  5. TTH

    TTH Senior Member

    I didn't know there were problems with 9mm and .45 ammo from Winchester-Western. It's surprising, anyway, since W-W had been in the ammo business for many years.

    The US M3 had the same accidental-discharge-when-dropped problem as the Sten, and so did other open-bolt wartime guns--MP40, PPSh 41, even the otherwise well made Lanchester. I'd like to see a comparative study or some statistics on the relative reliability of all these weapons.

    The Thompson had a big reputation, but the 9th Australian Division found that dust got to it (or to the magazines) and caused jams. It was common practice in the 9th Div to keep the Thompson in its dust cover until just before going into action.
    Last edited: Mar 10, 2019
  6. TTH

    TTH Senior Member

    Whenever you see US or British troops with the Thompson in wartime pictures, they always hold it by the forestock or forward pistol grip (depending on the model). The pictures I see of troops using the M3 show them gripping it by the magazine well--not the magazine itself.
  7. Don Juan

    Don Juan Well-Known Member

    The British generally seem to have had lots of complaints about the quality of US-made ammunition, and not just for small arms. 75mm tank gun ammunition was always alleged to be particularly badly manufactured.
  8. Don Juan

    Don Juan Well-Known Member

    One notable thing about the Sterling is that no matter how much better it may technically have been than the Sten, according to ARRSEpedia, the squaddies still loathed it:

    L2A3 Sterling - ARRSEpedia
  9. canuck

    canuck Closed Account

    Sadly, the Sterling functioned all too well for this gunman:

    The brave sergeant-at-arms, who spent four dangerous hours persuading Lortie to surrender to police, was Rene Jalbert, older brother to film and television actor Pierre Jalbert. Better known as Cage from the TV show Combat.
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  10. idler

    idler GeneralList

    There's a short section in the RAOC history that describes their intention to modify captured German 75mm AP projectiles to fit US guns. The reason was the softness of the US projectiles - something that's also been said about their armour; I recall the account of a .50" round penetrating an inch and a half into a turret. Perhaps it was the price of productivity?
  11. Don Juan

    Don Juan Well-Known Member

    The problems with the 75mm shell also extended to the cartridge case. One of the reasons for the delay in developing the British QF 75mm for the Cromwell and Churchill was the amount of misfires they experienced with the US ammo. I believe that one of the officers at the Experimental Wing at Lulworth received life-changing injuries due to this cause. The 76mm AP ammo was also sub-par due to being overly-brittle and prone to shatter, this being due to the process the Americans used to produce it.

    My understanding, which is admittedly far from comprehensive, is that the US did not have the metallurgical knowledge of the Germans or the British.
  12. Don Juan

    Don Juan Well-Known Member

    Some interesting Sten morsels from the 2nd Derbyshire Yeomanry.

    From Regimental Orders 20th March 1945:

    2 DY RO 20 Mar 45.jpg

    From Regimental Orders 27th December 1945:

    2 DY RO 27 Dec 45.jpg

    This regiment seem to have been quite a wild bunch:

    2 DY RO 20 Dec 45.jpg
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  13. canuck

    canuck Closed Account

    The Navy used hand grenades/TNT for fishing. The Army was obviously far more sporting in banning automatic weapons for game hunting.
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  14. Dave55

    Dave55 Atlanta, USA Patron

    US allowed semi-auto, apparently.


    Attached Files:

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  15. Juha

    Juha Junior Member

    IMHO that was some kind of design fault. With Suomi smg you could hold it by the magazine, at least the drum magazine (only magazine we used during our limited smg training) without any ill effects. IMHO it was natural to use the magazine as a handhold. Also in this video all shooters support the weapon with hand on magazine.

    Suomi smg begins 1:00 followed by the Soviet WW2 lmg DP-28. BTW at 3:20 begins kvkk-62, our lmg in those far away days of mid-70s. Suomi was an excellent smg but heavy and expensive to produce with its milled parts.
    I agree with the British test report table from summer 1940 even if I wonder the rof, we were told that Suomi smg had a rof of 900rpm.
    Last edited: Sep 20, 2019
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  16. Harry Ree

    Harry Ree Very Senior Member

    Interesting note as it has been recorded that 75% of ammunition was supplied to British Armed Forces was by the US through Lend Lease.
  17. Don Juan

    Don Juan Well-Known Member

    The Thompson had a single feed magazine like the Sten. Did the Suomi have a dual feed mechanism? That might be the difference.
  18. Juha

    Juha Junior Member

    Hello DJ
    In mid 70s my personal weapon was assault rifle RK 62 but we got some training with some other automatic weapons, i.a. Suomi smg, so my understanding on its working is limited. But IMHO it had single feed. In the drum the bullets/catriages were put into a spiral. This photo shows the inner part of the 70/72 rounds magazine
    it was somewhat ackward to load because its powerful spring but once loaded it worked well.
    More on Suomi smg
    Scroll past 7,65 mm Bergmann M/20 and Suomi protos until you get to 9 mm Suomi M/31 that was the smg Finns used during the WW2 and we still got some training with it in mid 70s.
    Last edited: Sep 21, 2019
    Don Juan likes this.
  19. Robert-w

    Robert-w Banned

    The Sten was designed to be mass produced by largely semi skilled workers. It could be made in quite basic workshops. Consequentially tolerances etc were quite lax and this included the fit of the magazine and at least one vet has complained that the one on his gun had a habit of falling off! I suspect that this is the real reason it could not be used as a handle. Presumably the Suomi was better made
  20. Juha

    Juha Junior Member

    Hello Robert
    yes, you are probably right, Suomi was good/excellent sturdy smg but heavy. But it was expensive to produce. British tested it and it was technically excellent but not what british needed, they needed smg which was cheap to manufacture and suited well to mass-production. Finnish WW2 soldiers liked Suomi very much but when Finns captured Soviet PPS-42 and -43 smgs Finnish top brass immediately became interested in them because they were easier to produce. A slightly modified version of PPS (modified to chamber 9 mm x 19 cartridges and to use the Suomi smg magazines plus some other small changes) was put into production as 9 mm smg model 1944, known also as "tin smg", it is the first smg used in the video I posted the link. It just missed the war. It cost appr. ½ of that what Suomi cost.
    To me firing Suomi was a dissapointment, after assault rifle it was like a toy gun, almost no recoil and fairly silent. But from 150 m or 100 m, cannot recall any more, I put almost all bullets from bursts into the torso of target, that was before body armour became commonplace, so surely would have incapaciate the other guy. And I was only an average shooter.
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