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9mm/.38 Super

Discussion in 'Gunsmithing and Repairs' started by briankk, Mar 11, 2013.

  1. briankk

    briankk Member

    How much should it cost to have my 9mm CZ52 barrel re-chambered to .38 Super?

    I've heard that the CZ will now and again have trouble feeding the 9mm, but the longer .38 Super works just fine, reference material says they have similar chamber pressures..
  2. rcmodel

    rcmodel Member in memoriam

    I wouldn't advise it.

    The tapered case of the 9mm measures .391" at the rear end, and the front .380".

    The .38 Super is a straight case, and is only .384" the full length.

    It would result in case bulging and possibly a blown case/ Ka-Boom.

  3. briankk

    briankk Member

    Makes since to me, how about 9mm Largo/9x23 Win, loaded to .38 Super velocities. I have some doubt about the strength of the barrel vs. 9x23 Win at factory loadings, but I mostly re-load everything for the result I'm looking for.

    Probably can't just bop on down to the gun store and pick up a set of 9x23 dies, though..
  4. rcmodel

    rcmodel Member in memoriam

    The 9x23 Win is just a rimless 38 Super case.

    9mm Largo is a tapered case & might work.

    But good luck finding anyone with a chamber reamer for it.
    And cases are next to impossible to get.
    Starline makes it occasionally, but out of stock at the present time with no projection when it might be made again.

    However, you said:
    Maybe you should try it in your gun yourself before you fix something that isn't broke.

    I would think most feeding problems could be addressed with magazine feed lip adjustment, if it proves necessary.

  5. briankk

    briankk Member

    Well, I already have a quite functional 9mm, an S&W99, and since I'm a long-time reloader, caster, etc, have a lot of 9mm bullets, and all types of powder, and primers and whatnot, the brass would be the only issue.

    I don't see any important differences between the Largo and the 9x23, but that the Winchester brass is designed to live under 55,000 something of pressure. I say "somethings", 'cause I've seen Winchester quoted as saying its 55k psi in one case, and 55k CUP in another, in any case pressures far beyond what I am interested in.

    Starline has 9x23 brass in stock, as of 30 seconds ago, but not not 9mm Largo. Hmm.. I've sent 'em an email about that exact question..
  6. rcmodel

    rcmodel Member in memoriam

    But the 9x23 is a straight case same as the .38 Super.

    It is smaller on the back end then the 9mm Luger case, just like the .38 Super.

  7. Jim K

    Jim K Well-Known Member

    How about the magazine, feeding and ejection port? The COAL of any of those rounds is greater than that of the 9x19.

  8. briankk

    briankk Member

    Well I show both the x23 and the Largo with 10 thou taper, base to rim, and both have same base dia. as the basic 9mm...

    But I see there is a lot of different opinion on the dimensions of the x23 reamer and the throat length, and my local 'smith hasn't a Largo reamer, whatever the throat is there..
  9. Legion489

    Legion489 member

    The S&W 39/59s were rechambered to .38 Super by Maj. Geo. C. Nonte and written up by him some time ago. Seemed to work fine for him. The mags forced him to use short bullets for an OAL that would fit. Also it is not that hard to do it yourself with drills if you are careful. Yes, there ARE acticles out there that tell you how to do it yourself published in the various mags or books. I'm sure there are You-tube videos or a quick web search will turn it up.

    If you have problems with the cases, just use cut down .223 cases (.38 Super Super? Can't remember what they were called back in the day) and that will cure any expansion problems! I would expect the mags to be a bigger problem (can you get .38 Super mags? Or just use the old ones?) than the rechambering or cases. .38 Super is about the ONLY ammo WallyWorld has on the shelf right now.
  10. BBBBill

    BBBBill Well-Known Member

    The good MAJ Nonte is dead, but his daughter is still around and kickin'. She's also a retired Army officer whom I converse with on occasion.
    As mentioned, the 39/59 conversions were limited to short 90 grain bullets to fit the action and work reliably. What you will not read anywhere is how well they held up. The service life of those guns was severely reduced. They took a beating.
    I have all of those old publications, hardback and magazine. Got 'em when they were new publications. They were interesting and exciting reads back then and are still good from a historical perspective. However, many of the techniques espoused then have proven to be wrong in light of more experience. You have to know the limits of the design and not many of us are experts in any of the fields that would provide that knowledge. I, for one, do not care to destroy a perfectly good gun or, worse yet, part of my anatomy to find out.
  11. briankk

    briankk Member

    I sent an email to Starline, inquiring about the difference between their x23 and Largo brass, they replied:

    "The main difference between our 9mm Largo brass and our 9x23Comp brass is the hardness of the head of the case. The 9x23Comp get hit a lot harder during the heading process to harden the head for better performance with high pressure loads. It also uses our tighter “Super” primer pocket while the Largo uses our standard primer pocket."

    It's not apparent from this reply that they see a dimensional difference between the two, and the only reamer rental place I found so far just calls out 9x23.

    http://www.9mmlargo.com/books/9x23.htm lists 14 different cartridges as "9x23", including the .38 Super Comp, never mind the case dimensions.

    I'm now thinking, re-chamber to 9x23 and load to, oh, say .38 super pressure, and measure the rollers a lot, should work out.

    Never have been able to find out what pressure the Largo was/is loaded too, so assume less that 9mm, FWIW.

    Reading around on the 'net, seems a lot of people shoot the .38 Super in the 9x23 chamber without ill effects, also FWIW..

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