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Thread: Shotgun-9mm thing

  1. #151
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    If you have a half decent lathe you'll be able to cut a thread on it. Just get a good lathe book and nut it out, tooling is usually the expensive bit if you don't have any, if you need anything like that done I have a mate here who has a lathe and mill setup at home and could do it.
    Boom, cough,cough,cough

  2. #152
    Gone But Not Forgotten Toby's Avatar
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    So the highest of the highest I have found in my data is 11,300PSI-12G and 61,500PSI-.308

    I dont have sub sonic loads for .308 so will have to wait until I get on the computer to have a look for that. Also don't know the other bit so will also wait till I get on the pc and google it

  3. #153
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    Well that will go well!
    Boom, cough,cough,cough

  4. #154
    Gone But Not Forgotten Toby's Avatar
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    I hope subs are better. I don't think a full load is bad either as its in its own barrel if thats right?

  5. #155
    Almost literate. veitnamcam's Avatar
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    Hint, work out the area of each case head.............................PSI stands for Pounds Per Square inch.
    Toby likes this.
    "Hunting and fishing" fucking over licenced firearms owners since ages ago.

    308Win One chambering to rule them all.

  6. #156
    OPCz Rushy's Avatar
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    Quote Originally Posted by veitnamcam View Post
    Hint, work out the area of each case head.............................PSI stands for Pounds Per Square inch.
    And the calculation Toby should be simple for a fellah like you. Just remember Big Ben Pies are Square.
    It takes 43 muscle's to frown and 17 to smile, but only 3 for proper trigger pull.
    What more do we need? If we are above ground and breathing the rest is up to us!
    Rule 1: Treat every firearm as loaded
    Rule 2: Always point firearms in a safe direction
    Rule 3: Load a firearm only when ready to fire
    Rule 4: Identify your target beyond all doubt
    Rule 5: Check your firing zone
    Rule 6: Store firearms and ammunition safely
    Rule 7: Avoid alcohol and drugs when handling firearms

  7. #157
    Gone But Not Forgotten Toby's Avatar
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    Hopefully I've got this right

    area for 12g - 0.6165"
    """""""".308-- 0.1750"

    I can't do the litte 2 off my phone to show its sqaured

  8. #158
    Almost literate. veitnamcam's Avatar
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    So thrust or pressure applied to the action for each is?
    "Hunting and fishing" fucking over licenced firearms owners since ages ago.

    308Win One chambering to rule them all.

  9. #159
    Gone But Not Forgotten Toby's Avatar
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    I googled and can't find a formula for that. Do you know one I can work off?

  10. #160
    OPCz Rushy's Avatar
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    Quote Originally Posted by veitnamcam View Post
    So thrust or pressure applied to the action for each is?
    VC you are subtly becoming quite the physics teacher. Keep it up and Toby will thank you for it one day.
    It takes 43 muscle's to frown and 17 to smile, but only 3 for proper trigger pull.
    What more do we need? If we are above ground and breathing the rest is up to us!
    Rule 1: Treat every firearm as loaded
    Rule 2: Always point firearms in a safe direction
    Rule 3: Load a firearm only when ready to fire
    Rule 4: Identify your target beyond all doubt
    Rule 5: Check your firing zone
    Rule 6: Store firearms and ammunition safely
    Rule 7: Avoid alcohol and drugs when handling firearms

  11. #161
    Gone But Not Forgotten Toby's Avatar
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    Starting to think me ditching physics for computing was a silly move on my part

    I found this

    http://en.wikipedia.org/wiki/Bolt_thrust

    Also got the formula



    6.96645 is a number I got for the 12g but have a feeling it's wrong and if it is right have no idea if it's N or lbs
    Last edited by Toby; 20-04-2014 at 10:10 AM.

  12. #162
    Almost literate. veitnamcam's Avatar
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    Quote Originally Posted by Toby View Post
    I googled and can't find a formula for that. Do you know one I can work off?
    Its pounds per square inch so

    12g - 0.6165" x 11,300psi = 6966 pounds of force trying to break the action apart
    .308-- 0.1750" x 61500psi = 10762 pounds of force trying (and possibly succeeding) to break the action apart.

    So we can see its in the bad idea bucket to run max power 308 out of the shotty action.

    If we take 6966 pounds of force as max and divide by 0.1750 case head diameter we end up with 39,805psi as max safe pressure.
    This is right around starting loads for 150gr in 308win.
    Data I have here for cast bullet loads(that you cant boot up the arse cos they are too soft) Is 170gr 2000 fps =37700psi, 1600fps= 21600psi.

    So it should be safe as houses subsonic or at reduced loads, the issue is making sure it is(if it was made) never fired with a full power load.
    Toby likes this.
    "Hunting and fishing" fucking over licenced firearms owners since ages ago.

    308Win One chambering to rule them all.

  13. #163
    Member Banana's Avatar
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    12g case head roughly 1.9cm diameter.
    1 inch = 2.54cm
    1.9/2.54=0.748 inches

    Area of a circle
    A=pi x r^2
    pi x (0.748/2)^2 = 0.439 in^2

    12g case head about 0.439 in^2

    0.439 in x 11300 psi = 4966 pounds bolt thrust

  14. #164
    Gone But Not Forgotten Toby's Avatar
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    It only be for subs. If I wanted a full .308 load I'd use the .308

    So my calculation is right by vc and wrong by banana? I got the measurment off chuck hawkes which is different to bananas

  15. #165
    Almost literate. veitnamcam's Avatar
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    I dont have one to measure but a quick google suggests 6-7k pounds thrust for 12g
    "Hunting and fishing" fucking over licenced firearms owners since ages ago.

    308Win One chambering to rule them all.

 

 

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