1. JadeX
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    JadeX Active Member

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    Can a 9mm Sten be modified to fire .45 ACP?

    Discussion in 'Research' started by JadeX, Jan 30, 2016.

    My characters have access to a small cache of .45 ACP ammunition (but no weapons to use it in) and instructions on how to build a British Sten 9mm submachine gun (but no 9mm ammo).

    I found this thread on a firearms forum about modifying the Sten's magazine to accept .45 cartridges, but that would be for using the Sten magazines in a firearm that is already chambered in .45, not a Sten itself.

    What changes would have to be made to the Sten, which is chambered for 9x19mm Parabellum, to allow it to fire .45 ACP? Or might changes need to be made to the ammo - some powder removed from the cartridge, maybe? IDK. If anyone knows anything about this kind of stuff I could really use the help.
     
  2. nippy818
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    nippy818 Active Member

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    different sized round. the 9mm is close to .38 cal. If he has everything he needs to build a sten gun he could easily up the ante and build it in .45. he would need a lathe to make the barrel and rifling bits. if its for close corridors and accuracy isnt an issue he can drill out the barrel to the .45 cal and go smooth bore.
     
  3. Samurai Jack
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    Samurai Jack Active Member

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    The .45 ACP is 11.5x32.4 mm compared to that 9x19mm.

    Every portion of the weapon that touches the bullet would have to be replaced. The magazine, the feed, the barrel, ejection port, firing pin. You'd be more or less building a new weapon, especially considering the Sten is stamped and welded, not really interchangeable parts. If I'm understanding it correctly.
     
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  4. Shadowfax
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    Shadowfax Contributing Member Contributor

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    In the Second Sino-Japanese War and the Chinese Civil War, both nationalists and communists used the Sten. Some Stens were converted by the communists to 7.62×25mm by using the magazine housing from a PPS to accept curved PPS magazines

    As I recall from being taught how to assemble/disassemble a Sten back in the '60s, it wasn't a rifled barrel, so drilling it out wouldn't be a problem. However, as @Samurai Jack points out, the firing mechanism would be more of a problem.

    Reading between the lines of the above extract from Wiki, it would appear that you could adapt it to fire the slightly smaller (just under 1.5mm) PPS bullets fairly easily. OK, the bullet's going to wobble as it goes up too wide a barrel, but Sten accuracy above 100m was dodgy anyway. It was better at short ranges anyway, where a spray of bullets almost requires design inaccuracy; a burst from a Sten would empty a room; a similar burst from a Bren would stitch the same hole in the wall every time!
     
  5. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    I agree that you would in effect be building a whole new rifle based on what the others have said. What time period does your setting take place in? A period rifle you might want to try and have them find would be a Thompson, seeing as it is designed to fire .45 ACP ammunition. Though you will still need to address the question of what time your story takes place in, as it will give a better indication of whether or not your idea is even feasible. From what I can tell it was not a decent weapon (Sten), but it remained in service from the 40's-60's. Not sure if it is even used anymore in the more modern day, considering its lack of accuracy and how many of the developed nations employ NATO specs into their armed forces rifles. The M-16 is I think the only diverse weapon that can handle both 5.56x45mm as well the NATO equivalent in size caliber bullet.

    Overall I found your characters predicament odd, considering they can find only caches of .45 ACP ammunition and 9mil weapons. Typically their would be crates of both ammunition and weapons together for ease of access in a war situation, and because the situation would demand bulk surplus. Effectively what you want to do is the equivalent of firing .22 out of a BB (.177) gun. There are modern pistols that can accept different barrels, but they have limitations to them, and I don't think they existed in WWII/Vietnam Era times. Just something to think about. :p
     
  6. JadeX
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    JadeX Active Member

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    Thank you. Sounds fairly complex, not something my characters would be able to do.

    For all intents and purposes, assume the setting to be 1962. While my book does actually take place roughly present-day, it follows the outbreak of World War 3 from the Cuban Missile Crisis, so basically anything that did not exist in 1962 does not exist in my story.
    Thus, the Thompson would have been one of the major infantry weapons in service at the time - that's presumably what the .45 ammo was for. What my characters have found is essentially "spillover"/surplus storage from a former armoury, and I've not yet decided what all is there. I don't want to make things "too easy" for them, so up to this point at least I've been avoiding "just giving them stuff" - like usable weapons paired with correct ammo.
    There may be some Thompson parts present, at least!

    Actually, they have found no weapons, just the ammo. They obtained instructions on how to build a Sten from elsewhere, so that's why there's a mismatch.

    I thought weapons and ammo were typically stored separately, though?
    Then again, considering there was WW3, perhaps that would warrant an exception...

    Good comparison, thanks.
     
  7. Shadowfax
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    Shadowfax Contributing Member Contributor

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    Instructions on how to build a gun would only work if they were already fairly proficient in gun-making, or at least metal-working at a fairly advanced standard. Complete with a well-equipped factory/workshop. But, if you've got instructions only, and you're good enough to follow them, there's no reason why you can't also make the modifications to accept a different bullet. The use of 9mm was to be able to use captured German ammo!

    The Sten was designed to be quick and cheap to manufacture, but it was still built in a factory, not a garden workshop. And build quality was dependent on just how good the factory was; Canadian-built guns were better than comparable British-built ones. I'm claiming that this was because most of the skilled workers were off in the army, and those building the guns were either old or newly-trained!

    In service, the Sten did what it was asked to do. It fired a lot of bullets, but not very accurately. At short range, that's a trade-off you'll accept. You'd never disable 3 men in a room using a standard rifle...you wouldn't be able to get off enough bullets before they'd rushed you.

    But, the Sten could jam, as one did in the assassination of Reinhard Heydrich; it could also discharge accidentally if dropped. It didn't need lubrication, a big plus in a desert environment.
     
  8. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    @JadeX I have sent out a question of your concept to a the few people I know that are in the service or have served, to find out if your plot makes any sense. Cause it is better to get a real world answer for even a fictional question. But from what you are saying it seems highly implausible based upon the evidence you present. You might as well make .45 weapons extinct or impossible considering your parameters. It would be like having all your tank munitions held by the Navy, because nothing about your concept makes any logical sense. But I will reserve my judgement until after I get an answer to the question at hand, if at all. Just trying to be helpful, not trying to knock the idea. Just don't want you to have a plot that doesn't hold any water. :D
     
  9. JadeX
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    JadeX Active Member

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    One of my characters is a certified welder and mechanic, and could easily build a Sten from instructions.

    How much work/knowledge would that take? I have characters that have access to all kinds of equipment and machinery, including welders, lathes, mills, etc. However, none of them know much of anything about firearms, as no civilian has touched one in about 40 years; having to learn about them will be a big part of the story build-up. The only person they know that has firsthand experience with firearms is a 73-year-old WW3 veteran who served as infantry in Cuba.

    All of which I'm aware of and will be accurately reflected. Thanks.

    Not sure what you're meaning. Of course there are .45 weapons - the M1A1 Thompson, the M1911, and the M3 "Grease Gun" were all in service at the time. My characters just haven't found any yet. They will eventually, they just haven't yet. What are you saying doesn't make sense?
     
  10. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    If you have all the necessary elements, and surplus of those elements then scarcity is artificially created as a conflict that need not exist. Unless there really is no weapons manufacturing taking place or has halted decades prior, in which case your scenario makes complete sense. But only if that criteria is met, cause it would cause a shortage based upon caches being destroyed from bombardment and lack of manufacturing. If neither is the case then your making it far to difficult on your characters to find what they need. They would have a fairer chance of reloading spent 9mm casings than worrying about finding weapons to fire .45s, they could simply use the primers and gunpowder in the 9mm casings and shave down the bullets to fit. In theory anyway, they would find a way to solve their problem until they find another solution. People are pretty industrious when the need arises. Just a thought.
     
  11. JadeX
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    JadeX Active Member

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    There ya go.

    My story takes place roughly 2014-ish, and no firearms have been made since 1962/1963. My characters are working to build an armed resistance against a totalitarian government (which does have its own weapons). Acquiring arms and learning to use them in a world where no civilian has touched a firearm in almost 50 years will be the first major hurdle they will have to overcome, and will be a heavy part of the build-up/exposition phase of the story. The veteran character I mentioned will be there to help teach the basics of firearm operation, combat training, etc., although his usefulness is limited by his age (73+) and the extent of his personal knowledge - I'm not sure how useful he might be in modifying firearms and their design (because he wasn't a machinist or anything, just rifleman/infantry).
     
  12. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    Ok that explains it better and would be plausible. I did get an answer from my brother in-law as far as weapons caches are concerned, and he agrees with you to a degree as far as how they are kept. He would know he is Ranger, and has been on tour a few times.

    Here is what he said:

    So, to answer your first question: yes ammo and weapons are stored separately. The arms room is in the unit footprint, the ammo holding area is often in a separate area of post. There are no other caches of weapons that we use. the second part is less likely, converting a 9mm SMG to fire .45 ACP is much trickier than the .45/9mm conversion owing to the fact that many SMG's chambered in 9mm have receivers, bolts and other part dimensions that cannot accommodate the additional length, width and height of the .45 ACP. Hell, the magazine well and ejection ports could all prove problematic. Would it be easy to find SMG's or other small arms on the battlefield.... it depends. If a unit is left in tact enough to retreat, they should take all of the fallen and their weapons with them. In a catastrophic defeat from the air, weapons could be left on a battle field, but force on force, weapons would be either captured or destroyed by the winning units. Hope that help buddy.

    Hope this helps you with your story as well. :D My Brother in-law is kind of my go to guy for gun related stuff, cause he collects them. :p
     
  13. JadeX
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    JadeX Active Member

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    That does help, thanks!

    Here's an idea, maybe:
    Instead of trying to modify the gun itself, might it be easier to modify the cartridges? The lead bullet can be shaved down to a smaller size, and you'd mentioned before about using the .45 primers in a 9mm casing... so can the brass be modified somehow to the dimensions of a 9mm casing? Because if so, then I should be set, right?
     
  14. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    I am not to sure on that one. I think if you can make a mold for a smaller casing you could melt down the brass to the right caliber, even if it is crude it could work though you might have some problems. Maybe you could crimp the .45 down to fit, but that might cause a whole new set of problems that no one needs. So unless they can find spent 9 mil to reload with the .45s, casting the brass would be the reasonable option.
     
  15. JadeX
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    JadeX Active Member

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    "Casting" as in, like what they do in a foundry?

    Because that will totally work with my story! Many of my characters are blue-collar type workers, a lot of metal workers and machinists and such, so surely somebody knows somebody that can do that.
     
  16. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    Exactly, just not on an industrial level. There is plenty of source material available for DYIers on casting with what you have available in a household type environment. All you need to do is find out what types of materials are needed for the molds, and finding the fuel and materials for a makeshift furnace. I think you could find those things in common place artifacts. Hell I found a backyard metal working webpage that can offer you some ideas. Although you can also cast casings from other metals if you need to (like AK rounds have both bras and steel casings for example). :p


    http://www.backyardmetalcasting.com/
     
    Last edited: Jan 30, 2016
  17. JadeX
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    JadeX Active Member

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    Awesome! That definitely makes things a whole lot easier. So now they can make their own cartridge casings for whatever size they need, as long as the lead can be made to fit.

    What kind of changes would need to be made to the primers to make them usable?
     
  18. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    I don't think the primers need to be messed with, only the amount of powder should be less for the smaller caliber. You will have to remove the primers and seat them into the new cast casings, but not need to be alter them. Other than that you should be good to go with manufacturing 9mil ammo. 95-127 grains of powder for a 9mm, and roughly 155-230gr for .45 ACP. Just for an accurate load reference on gunpowder.

    I apologize for being an ass earlier. :D I am glad I could help you with your research, and hope it goes well for you. :)
     
  19. JadeX
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    JadeX Active Member

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    Nah, you just misunderstood something apparently. Thanks for the info, it helps a ton! Oh, and another way you helped me earlier:

    I knew weapons and ammo were stored separately but I didn't know that weapons and ammo could be stored in different parts of the same base. That helps, because this ammo cache is located in a [fictional] tunnel system under a city (circa 19th century, presumably of Freemason origin), which was commandeered by the DoD in the early Cold War and converted to a military tunnel base in case of Soviet invasion - the tunnels were to be cemented and nuclear hardened and connect to several strategic locations in the city, but the project was abandoned in 1951 due to the outbreak of the Korean War. Alan, the WW3 veteran who knows about the tunnels, does not know if the project was ever actually started or not. Turns out it was, and that's where the .45 ammo was stored.

    So, perhaps the ammo could be stored at a random location somewhere along the tunnels, while weapons could be stored in the part of the tunnel located under the armoury - as long as that section is sealed off from the rest of the tunnel system, it should suffice. Remember how I said they hadn't found any .45 weapons yet? Now I know where they can!
     
  20. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    Well that is good, and I thanked my Brother for you and myself. Glad that you have it all worked out. :)
    And now you have a back up plan in case you need to convert caliber down for bullets, up is also doable but will cost more resources.
    I am just glad to be able to help a fellow writer in some capacity. :D
     
  21. psychotick
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    psychotick Contributing Member Contributor

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    Hi,

    Odd question from someone who knows bugger all about guns. But why would they find the plans to a sten gun of all things? Honestly if you were going to pick a weapon that everybody seems to have plans for all over the world - wouldn't an AK47 be the one? And it's been around since the end of WWII.

    Cheers, Greg.
     
  22. JadeX
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    JadeX Active Member

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    You can't build an AK47 out of nothing. It's far too complex. The best thing about the Sten was its simplicity. It could be built anywhere by anyone with minimal materials and minimal machining. That's what made it so popular among resistance groups at the time, most notably the Warsaw Uprising. It fits in perfectly with my story.
     
  23. Samurai Jack
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    Samurai Jack Active Member

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    I'm not very good with options. I'm too fixated on the immediate problem. I don't know if it's because I'm short sighted, or because I prefer an OP to come up with the options *shrug*

    If you walk onto a Western military base, there are going to be dozens of one room vaults containing a company's weapon systems for personnel and vehicles. None of them will contain ammo.

    Ammunition for everything from a handgun to artillary shells will be in a very few specific guarded locations for safety and accountability reasons.

    In an outpost or combat environment, there will still be a central location for most ammunition, but individual units will have combat loads given to them, a few hundreds of rounds per weapon.

    So, essentially, in any situation someone finds ammunition in a military complex, there is more than probably going to be a weapon system somewhere in that area, and vise-versa. Maybe there won't be enough of those weapons, or maybe there won't be the tools necessary to duplicate them, but they will be there.
     
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  24. Samurai Jack
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    Samurai Jack Active Member

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    And, while I'm thinking about it, making ammunition is easy for anyone fimiliar in machine working, as you describe your characters to be. Getting a single round to survive multiple firings requires longer processes, better metals, and more attention to detail. But making ammo in bulk to simply put rounds into targets isn't complex.

    So, you can certainly reshape and cut larger rounds into smaller ones. The process would more or less be a continuation of manufacturing the original round.

    But if characters will have access to the raw materials they might be better off making rounds from scratch.
     
  25. Cave Troll
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    Cave Troll Bite the bullet, do your own thing. Contributor

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    @Samurai Jack I don't think you can shave 2.5 mills off the thin walls of a shell casing. There simply is not the material to just shave it down. And crimping would cause a whole host of problems like feed jams, misfiring, and exploding the chamber, all of which would not be good. Along with destroying the barrel by not having the proper size projectile. You can get away with being hari-kari about what you fire if you are using a 12g shotgun, I have seen a guy that makes and uses experimental loads, from machined bullet shape slugs to using washers and exacto-knife blades. One thing that channel has taught me is that those giant gummy bears are bullet proof. :D And you can fire quite a bit of things from a 12g, not that it is recommended to use the many types of things they do as bullets, in an emergency situation you have a ton of things to reload 12g shells with. The motto is: If it loads it can be shot. :p
     

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