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1911 9mm to 38 super conversion

Discussion in 'Gunsmithing and Repairs' started by gary@r&g, Jun 11, 2004.

  1. gary@r&g

    gary@r&g Well-Known Member

    Does anyone know what all has to be done to a 1911 (STI Trojan) in 9mm to convert it to 38 super. In addition to fitting the BBL will the ejector have to be cut?

    Thanks! Gary
  2. 1911Tuner

    1911Tuner Moderator Emeritus


    Howdy Gary,

    It's usually a pretty simple switch. With single-stacks, it's a matter of
    the barrel or rechambering the 9mm barrel with a .38 Super finishing reamer. There might possibly be an issue with the breechface, but that's not a major adjustment in the rare instances that it needs it. You'll need different magazines, and you may need to up your recoil spring rate to 13-14 pounds. Most 9mm to .38 Super conversions are straightforward...Once
    in a while, minor issues show up that are just a matter of a tweak here and there to correct.


  3. gary@r&g

    gary@r&g Well-Known Member

    1911 38/9mm

    Tuner, thank you for your quick response. If I do it I will use a new barrel. I had heard that the 9mm uses a longer ejector that would have to be cut to use 38 super. Thanks again!!!!
  4. 1911Tuner

    1911Tuner Moderator Emeritus

    re: Ejector

    Howdy again Gary. Mighty welcome.

    The ejector SHOULD work okay as is...There's always a chance of
    havin' to tweak the nose a little for best function, but that's true of
    any ejector...even with an ejector swap in the same caliber. The length
    of the extractor hook is more likely to cause a problem in the ejection cycle,
    but that's an easy one to spot and adjust.

    If the empty case gets hung up part-way out of the port at an angle...the
    hook probably needs to be shortened about .003 to .004 inch...or about
    one sideways swipe per thousandths on a smooth mill file, and lightly
    radiusing the bottom corner of the hook. Since there's a little difference in the rim diameter between the two rounds, you'll probably have to re-set
    the tension.


  5. grendelbane

    grendelbane Well-Known Member

    I am going to have to disagree with Tuner about the ejector. Don't worry, I don't intend to make a habit of it.:)

    I have seen, (and currently possess), 9mm's which had an extended ejector that would be too long for a loaded .38 Super to eject. This would not stop you from firing, since that is when we eject empty cases. It would make it difficult to unload without firing, however.

    I have swapped .38Sup to 9mm, and also 10mm to 9mm. The last one is supposedly not real reliable because the 10mm breechface is a little bit larger, and the ejector is not extended like the 9mm. Also, the extractor is not proper either.

    Still, at least with hardball, my Delta 9 has been reliable. In fact, when I was having extractor issues, it was more reliable in 9mm than it was in 10mm!:banghead:

    My latest project is a Colt .38 Super slide, cast Caspian frame. This is the one with the extended ejector. Right now, it has a 9mm barrel. Soon as time permits, I will shorten the ejector and install the .38 Super barrel.:D

    As Tuner notes, I may have to tweak the extractor at that point.
  6. 1911Tuner

    1911Tuner Moderator Emeritus


    I am going to have to disagree with Tuner about the ejector. Don't worry, I don't intend to make a habit of it.

    Ain't gonna dispute your word on that...I've got limited hands-on with either caliber, and even less with the conversion. I can see how an ejector tuned to length for the 9mm would need to be shortened a little for the Super. Sometimes I have to adjust the length on .45s...especially
    on Commander-length pistols...even with ejectors that are made for'em.

    Sometimes live-round ejection requires a little work on the front of the port, right in the lower radius.

    Bottom line is to expect to have to make adjustments in certain areas on any pistol when you swap out parts. When going from one caliber to another, it's pretty much a given that a few things will need to be custom fitted and/or tuned.

    Good point grendelbane. Kudos!

  7. grendelbane

    grendelbane Well-Known Member

    I have a limited experience in swapping calibers. My best advice is not to expect great reliability. I have surprised myself several times, however.

    .38 Super to 9mm, and vice versa is the easiest. Both cartridges use almost the same diameter rim. Therefore, the breechface is almost the same.

    Extractor differences are so close as to be accomodated under "tweaking".

    Magazines are different, for the different length cartridges.

    Short cartridges, (9mm, .40 S&W, 357 SIG). will normally work with ejectors intended for long cartridges, (.38 Super, 10 mm, .45 ACP). There may be reliability issues, and I do not recommend such a situation for anything but range purposes.

    Personally, for reliability, I think that a pistol, (frame, barrel, slide, extractor, ejector), should be dedicated to a single caliber.

    For practice, range use, and other non serious purposes, caliber swaps may make sense.

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