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Thread: BLOW BACK IDEAS W LESS AK PARTS

  1. #21
    Gunco Good ole boy kernelkrink's Avatar
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    The Tommy used a fixed ejector riding in a slot in the bolt, very similar to the AK setup in principle. Since the square rear section of the bolt riding in the receiver kept everything aligned, they went with a much simpler ejector instead of a rail. Just a threaded hole in the left side of the Tommy receiver and a screw with a flattened end is screwed in. To keep the flat properly aligned the head of the ejector screw was a small oval shaped flat spring steel piece with a dimple in it. This dimple fit into a shallow hole on the outside of the receiver to index it properly.

  2. #22
    Gunco Veteran muttman's Avatar
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    Quote Originally Posted by Prototype Services View Post
    Federal law. Has to be closed bolt.
    it was ment as a joke, but if you did not get it then the joke is on me.

    muttman

  3. #23
    Gunco Member deth502's Avatar
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    Quote Originally Posted by kernelkrink View Post
    "Limits" on blowback have more to do with size and weight of components rather than pressures. The HK G3 rifles are a roller delayed blowback action. I forget the exact numbers, but a .308 rifle would require a 30-something pound bolt in order to function as a straight blowback. The roller mechanism on the Hk creates a "mechanical disadvantage" so the rearward pushing cartridge case isn't inhibited solely by the inertia of the bolt and carrier. This lets them drop the bolt/carrier weight and size to something practical for a shoulder fired weapon. They also use a fluted chamber so gas from firing can "float" the case within the chamber, otherwise the case would stick to the walls and prevent operation.

    AMT made a .22 magnum rimfire pistol, IIRC they had to machine rings into the chamber so the case would swell into them to delay blowback.
    THANK YOU for that post!!!!!

    everything was correct.

    its refreshing.

    had some instances on a few other sites latley where people had some completley off teh wall theories and when i tred to explain how these actions works, their right and im wrong!?!?!


    and as for the "window" for the fcg, yes, thats how my build is set up, the sgn9 inspired one.

    another thing to think of, if you were to find a double hook ak trigger, and cut off the "wrong" end to make it a single hook, you could have a guide rod/recoil op ejector and the spring on it, like the ppsh43 set up. (using a std single hook would have teh cases eject out the wrong side)

  4. #24
    No Hope For Me 1biggun's Avatar
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    another thing to think of, if you were to find a double hook ak trigger, and cut off the "wrong" end to make it a single hook, you could have a guide rod/recoil op ejector and the spring on it, like the ppsh43 set up. (using a std single hook would have teh cases eject out the wrong side)
    FINDING A DOUBLE HOOK AND CUTIING OFF THE LH SIDE WOULD BE NO PROBLEM. .
    NOT FERMILULAR WITH THE PPSH43 HOWEVER. BUT HAVING A GUIDE ROD MAKES SENCE TO ME.

  5. #25
    No Hope For Me 1biggun's Avatar
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    THE WEIGHT OF A SUNOMI BOLT IS CONSEDERABLY MORE THAN A ak BOLT AND CARREIER.
    GETTING ENOUGH WEIGHT INTO A BOLT WITH OUT A PISTON ROD AND ALL THE EXTRA STUFF ON A AK BOLT ABOVE THE BARREL.

    iM JUST THINKING ALOUD HERE. WAS KIND OF LOOKING AT FITTING THE SUNOMI BOLT TO THE AK RECIVER AND RAILS. IT COULD BE MILLED SQUARE BUT IT IS PRETTY LONG. IT WILL NEED TO SLOTED OUT IN THE CENTER FOR THE TRIGGER ECT. YOU COULD JUST CUT OFF THE BOLT FACE END AND ADD IT TO A SQUARE BLOCK. A TUBE BUILD MATED TO THE RECIVER AS MENTIONED ABOVE WOULD BE LIKELY A LOT EASIER. hmmmmmmmmmm

  6. #26
    No Hope For Me Coils's Avatar
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    I liked you ideas in the first post, making a simple trunion and squarish bolt carrier to fit in an AK receiver, and using a standard AK bolt and pinning it in the home made carrier (so it can be removed for servicing).
    It sounds like you wanted to do something as simple as possible with as little work as possible, it seems like this thread is straying toward a more complexed approach now.

    Although I really didn't add anything helpful, this is my $.02.

  7. #27
    Happy Camper hcpookie's Avatar
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    Kernel's description of the skinny hammer approach is how I believe the semi-only Sten guns are/were built. I remember seeing details of that somewhere but I think it was a forum post of someone showing off their new toy, not necessarily a "how it works" post.

    The 9mm bolt in that case is basically a chunk of metal big enough to fit inside the receiver, and has a slot cut in the bottom for a hammer. Everything else would be the same... extractor, firing pin, recoil spring guide hole, etc. Applying this to the AK parts set, you need at least half of the hammer to be exposed for the sear to catch it. There is definitely enough room to work if you make a heavier bolt that is the same basic shape as the AK bolt/carrier.

    The Russian Bizon SMG used the original bolt carrier design since it was a known dimension for them, and kept the front extension presumably to keep it aligned so it won't slide over the magazine, rather keeping it pushed down in the front to prevent fail-to-feed issues. Presumably. Or maybe they wanted the extra weight, I really don't know. I know that Rhino used it for a weighted rod for his blowback AK.45 project.

    The fact that 9mm is so under-powered, you could use relatively soft metal on the bolt. I know for a fact that Suomi bolt, being for a WW2 bullet hose of a weapon, is really hard steel! That would be rough on your cutting tools. You definitely need to anneal it before cutting on it! Also, think about the size of a pistol's chamber area... I think you could use basic 1018 metal and heat treat it, and that may be enough for a bolt. And for a trunion, honestly.
    Gunco Member #10

    http://pookieweb.net


    The "original" Boltcutter Rivet Squeezers:
    http://pookieweb.net/AK/rivet/boltcutters/boltcutter.htm


    Project Pink - the Pink and Blue AK-74:
    http://pookieweb.net/pink/pink.htm

  8. #28
    No Hope For Me 1biggun's Avatar
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    I liked you ideas in the first post, making a simple trunion and squarish bolt carrier to fit in an AK receiver, and using a standard AK bolt and pinning it in the home made carrier (so it can be removed for servicing).
    It sounds like you wanted to do something as simple as possible with as little work as possible, it seems like this thread is straying toward a more complexed approach now.

    Although I really didn't add anything helpful, this is my $.02.
    YEA AS SOON AS I STARTED TO THINK ABOUT TRYING TO GET THE SIGHT PLANE DOWN IT STARTS GETTING COMPLICATED.

    I WANT TO BE ABLE TO USE A SUNOMI MAG AND LIKELY THE BARREL FOR AT LEAST ONE BUILD. IM NOT A BIG FAN OF WELDING THE BOLT TO THE CARRER ALMOST NESICATING AN AK KIT. i CAN LIKELY MOVE THE BARREL UP SOME AND STILL RUN A STOCK SPRING.

    IM NOT SURE ABOUT NEEDING THE WHOLE GAS PISTON AS A GUIDE ROD. i WOULD WANT A BETTER FITTING AND HEAVYER RAIL/ GROVE SYSTEM IF i GOT RID OF IT. OR POSSABLY A ROD INSIDE THE SPRING THAT RAN THROUGH THE BOLT.

    i KIND AM ALL OVER THE PLACE HERE. i WANT A 17 HMR IN SA AND WAS THINKING A MODIFED 22 LR COULD BE DOABLE. i LIKE THE GERMAN MUCH MORE THAN THE ROMY 22 LR. AND THAT GOT ME ON THIS WHOLE HEY LETS REDESIGN THE THE AK.

    LOOKING AT THE SUNOMI BOLT IT DOES SEEM LIKE IT COULD HAVE THE SMALLER ID AREA CUT OFF AND USED IN A SQUARE BLOCK. AK BOLTS ARE STILL REASONABLE. AS WELL AND THEY ALREADY HAVE THE FIRING PIN INSTALLED.. TO BUILD A SHORTER RECIVER A SHORTER BOLT WOULD BE NEEDED AND THAT WOULD MEAN CUTTING DOWN THE AK ONE OR A NEW ONE. RIFLE REALLY DONT NEED TO BE SHORTER PISTOL WOULD GREATLY BENIFIT FROM IT. LIKELY NEED TWO DESIGNS A AK CLONE WITH NEW TRUNION, AND A COMPLETLY CUSTOM FROM SCRATCH 17HMR.

    A QUICK QUESTION. IS THE TANG/STOP REMOVED FROM THE REAR OF THE CARRER(THE ONE THAT PREVENTS OUT OF BATTERY FIRINGS) FROM A NORMAL AK BLOW BACK BUILD? IF SO HOW ARE OUT OF BATTERY FIRINGS PREVENTED? ITS GOT TO BE SAFE ONCE DONE.

  9. #29
    No Hope For Me 1biggun's Avatar
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    THERE WERE STEN,S WITH BRONZE BOLTS. i HAVE ONE OF THOSE KITS AS WELL NOT SURE WHEN IT WILL GET DONE.

    TO BE HONEST THE WHOLE 9MM THING DONT REALLY EXCITE ME MUCH. iTS REALL TO LIGHT TO HUNT MUCH LARGE GAME WITH AND TO BIG FOR SMALL GAME. iT WOULD BE MOSTLY A TOY FOR ME.

    A 22LR OR A .17 WOULD GET THE HELL SHOT OUT OF IT. I WISH THE ROMMY TRAINERS WERENT SO PRICEY. $300 FOR A .22 THAT DONT SHOOT VERY ACCURATLY AND HAS JAM ISSUES IS TO MUCH IMOA. I WOULD LIKE ONE TO CONVERT INTO A VARMIT CLONE OF MY 223 VARMIT ak IN 17 HMR HOWEVER. PERCISION BARREL CUSTOM STOCK BIG OPTICS

  10. #30
    Gunco Veteran muttman's Avatar
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    big gun,
    you need to stop this and see the beer girl and drink a pair. after that think on this one,
    look up a robison arms .223 gun. the bolt carier and piston are what look like a long rod with a chunck of rectangel steel on the lower side. the long rod would add the LBS. that is needed, and a place to mount the charging handel ( AK or GALIL style) the bolt sits in the rectanguler steel. if you were to cut slots in the rectangular pice to help guide the hole thing and a homemade bolt head using a CZ52 extractor or a homemade type and your there. BTW what kind of mags are you using?

    the .17 could be made the same way just with a diffrent extractor. and that has me eyeing that build now, but that will haft to be next year, thinking of a pps43 from scrach with a left over chunck of barrel if I can rent a reamer.

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