7.62x25 chamber pressure

Discussion in 'The Powder Keg' started by jmp8927, Apr 28, 2010.

  1. jmp8927

    jmp8927 G&G Enthusiast

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    I couldn't find any specs on the chamber pressure of the 7.62x25mm online, so I thought maybe some of y'all would know. I was looking at some of mine today, and realized that the casing is very similar in size to a 9x18mm and I was wondering if a 7.62x25 was fired in a 9x18 pistol, could the casing be trimmed down to a 9x18mm? I just want to make sure it's safe first. I'm pretty much sure it would be fine since there's a 1.5mm difference in bullet diameter, but figured I'd be safe and make sure.
    Last edited: Apr 28, 2010
  2. gandog56

    gandog56 G&G Enthusiast

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    Why bother when it is so much easier to just trim a 9mm Luger case down? More free cases of them to be found for free at the range.
  3. Big Dog

    Big Dog Dinosaur Wrangler Forum Contributor

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    7.62X25 will NOT chamber in a 9X18 pistol, and if it could, it would destroy the pistol, and likely your hand........
    Now, cutting the case down and loading to 9X18 spec - that may work. You might do the same with .223Rem cases too. I have read of the .223Rem being used to make reloadable 7.62X25. Diameters aren't exactly the same, but some fellers do it.
  4. samuel

    samuel G&G Newbie

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  5. jmp8927

    jmp8927 G&G Enthusiast

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    Um, 7.62x25 WILL chamber in a 9x18 almost perfectly. All measurements at the base of each casing is within 0.005" with the 7.62x25 being the smaller. Brass will expand easily and so it will be the correct size after firing. My thinking is that because the bore of my 9x18 is 1.5mm larger, the 7.62x25 will not be able to create over-pressure because of all the gas leakage around the bullet. I'll take some pics of the two side by side along with a 7.62x25 chambered in a 9x18.
  6. jimkim

    jimkim G&G Newbie

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    Better yet, just use free 9x19mm brass.

    [ame=http://www.youtube.com/watch?v=_yrmgh3SToE]YouTube - Making a 9x18 Makarov From a 9x19 NATO/Luger[/ame]
  7. jmp8927

    jmp8927 G&G Enthusiast

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    Here are some pics

    [​IMG]
    [​IMG]


    This is how a 7.62x25 fits in the chamber.
    [​IMG]


    This is a 7.62x25 chambered with slide closed.
    [​IMG]
  8. jmp8927

    jmp8927 G&G Enthusiast

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    ^I'm planning on using 9x19. However, I don't own a 9x19 yet, so I have to wait until someone I know shoots it or buy it and have it shipped to me. I don't go to a range to shoot, so I can't collect any. I do have a 7.62x25 chamber insert for my Mosin Nagant, so now I have something to shoot 7.62x25. I also would like to buy a 7.62x25 upper for my AR-15 when I can afford it. This is just to give me more options. I like options.
  9. jimkim

    jimkim G&G Newbie

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    From memory the 7.62 brass is a good bit smaller in diameter, at the web, that the 9mm Mak. I wouldn't do it.
  10. Big Dog

    Big Dog Dinosaur Wrangler Forum Contributor

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    I would still caution to NOT fire full-power 7.62X25 in a Makarov pistol - no sense giving that much control to Mr. Murphy........ :boggled:

    My opinion only - YMMV of course....... :veryhappy:
  11. jimkim

    jimkim G&G Newbie

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    I think we are in agreement.
  12. jmp8927

    jmp8927 G&G Enthusiast

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    Welp I took a 7.62x25, pulled the bullet, dumped 25-30% of the powder, shoved the bullet back in and fired that. Predictably weak and it did expand the brass a lot, but not quite enough imo. I fired a full load after that and it was a little more power than I'm comfortable with, but it did expand the brass all the way to the chamber walls, so that there shouldn't be any problems trimming and resizing to the exact right size. I'm thinking a 90% powder load would do the job if it had to without the possibility of damaging the pistol. My conclusion right now, it can work but isn't worth the trouble to go to unless 9x19 brass is unavailable.
  13. eagle4g63

    eagle4g63 G&G Newbie

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    jmp8927 If you have re-loadable 7.62x25 than I would be willing to do you a really nice trade for plenty of 9mm luger brass all re-sized and de-primmed, all you would have to do is trim!!! I would even cover shipping both ways!! If it is loaded ammo you have than maybe I would even be willing to trim it also. Just let me know. I got rid of my 9mm and have lots of brass left over.
  14. jmp8927

    jmp8927 G&G Enthusiast

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    I don't have reloadable brass right now. Not unless you want to reload berdan. It is brass though. I'll eventually buy some boxer primed 7.62, especially if I buy something else that shoots it. I'm definitely interested in any 9mm brass though.
  15. Kaybe

    Kaybe G&G Enthusiast

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    Where did you get a 7.62x25 chamber insert for the Mosin? If they work well, I might just break down and get an old Russian whore of a rifle to play with. Don't tell my Mausers
  16. jmp8927

    jmp8927 G&G Enthusiast

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    Sportsmansguide.com They just got them a couple weeks ago.
  17. Kaybe

    Kaybe G&G Enthusiast

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    .303 or 7.62x54r. Are they both that close to be interchangable with an insert? Not sure if that would work. Anyone use those things?
  18. gandog56

    gandog56 G&G Enthusiast

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    No, you would need one of each insert as far as I know. When you go to order it has both listed separately in color/size.
  19. jmp8927

    jmp8927 G&G Enthusiast

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    Right. You click on a drop down menu and select the one you want. Those two calibers are not interchangeable at all.
  20. res45

    res45 G&G Regular

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    jmp8927 from one reloader and shooter to another DON'T EVER fire another cartridge in a firearm that isn't chambered for it,the X25 head spaces on the cartridge shoulder while the 9 x 18 head spaces on the cartridge case mouth.

    Part of the case the shoulder and case neck is actually sticking way into the rifling if you load an x25 in a 9 x18 pistol,also the 9 x 18 pistol slide,frame and recoil spring are not designed to handle the pressure the x 25 generates. The average x 25 rd has a standard muzzle velocity of 1500 fps. while the 9 x 18 is around 1100 fps. plus the fact that the x25 fires a .308 dia. bullet while the 9 x 18 fires a .365 dia bullet. If it wasn't for the fact that your x25 rd has a smaller dia bullet and just blew out and allowed the pressure to bleed off the gun probably would have exploded in you hand.

    The side by side pic you have of the 9 x 18 and x 25,everything thats above the case mouth of the 9 x 18 on the x 25 rd is in the rifling of the 9 x 18 bore. On the low side the pressure of the x 25 rd is around 31K I'm sure the surplus loads are up around 33 to 35 K PSI while the 9 x 18 load is in the low 20K PSI range for a max load.
    Last edited: May 1, 2010
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