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9mm Bullet Through .38 Special Barrel?

Discussion in 'Gunsmithing' started by doc540, Feb 12, 2010.

  1. doc540


    Apr 25, 2007
    Deep SE Texas
    Supposing all other factors (cylinder bore, pressure rating, etc) were acceptable, could a 9mm bullet be shot through a barrel bored for .38 Special?

    And, if so, could it be "reasonably" accurate out to 15-25 yds.?:dunno:
  2. Glock2008

    Glock2008 Gun User

    Jul 16, 2008
    Up north
    Yeah it will work. I'm not sure how accuarate though. At 15 yards it might not be so bad. If your using lead bullets it may work out to 25 yards as the bullet should slug up to the barrel size, as i believe a 9mm is a .356 bullet and a .38 is a .357. I have never tried this though.

  3. I wouldn't bother. The .38 is a rimmed cartridge, the 9mm isn't. It would Probably slide forward in the cylinder to make it impossible for the firing pin to strike the primer with enough force to set it off.
  4. GIockGuy24

    GIockGuy24 Bring M&M's

    Jul 14, 2005
    With Amber Lamps
    Many Colt revolvers have bores that are very tight or exactly what would be considered 9mm. Ruger made switch-cylinder Blackhawks in 357 / 9mm and some people report that accuracy isn't very good with 9mm bullets.
  5. Singlestack Wonder

    Singlestack Wonder

    Nov 15, 2003
    9mm is actually .355". The .38 Super is .356". The .38 and .357 are .357".
  6. doc540


    Apr 25, 2007
    Deep SE Texas
    Apart from the issue of "yes or no", how would you approach the idea of converting a D frame Colt from .38 to 9mm?

    It appears a new cylinder would need to be machined.

    What say you?
  7. srd


    Apr 4, 2009
    I used to own a .357/9mm Blackhawk convertible. Yes it had an interchangeable cylinder. Accuracy with the 9 was poor at best with lead bullets. Leading was also an issue due to the .358 dia barrel and the .356 dia. 9 mm. I still have the 9mm cylinder for it but the rest was stolen several years ago. Would i buy another one to play with ? No
  8. back in the 80's i had a hunter pistol silhouette load that was a speer 88gr hp seated inside a 357 case. the bullet was seated down inside the case on top of the powder. i shot this in a 357 mag thompson center contender. this was a good load and was shot by many during matches. i have seen many 38/39 hits out of 40 during a match with this load. had something to do with the forceing cone of the tc barrel that made it work. don't know whom came up with the load, i just used it like several others.
  9. 1006


    Aug 12, 2007
    Newnan, Georgia
  10. doc540


    Apr 25, 2007
    Deep SE Texas
    Spoke with Mark last week.

    He machines factory S&W cylinders but can't convert a Colt .38 cylinder to 9mm.

    Super nice guy that does some GREAT work. Everyone should visit his site and look at the work he's done!
  11. jaysouth


    Feb 15, 2001
    Confused in TN

    Those are "nominal" dimensions. Without actually slugging your barrel, you are guessing. Depends upon individual manufacturer.

    I had several thousand 115 gr. SWC cast bullets sized to .356. Worked fine in .38 Model 14 smith and fine in a Glock with Lone Wolf barrel.

    The difference between .355 and .357 is less than the thickness of a cigarette paper.

    Each and every barrel is a law into itself.
  12. doc540


    Apr 25, 2007
    Deep SE Texas
    Received a reply from Jim at FAMCO today:

    Sorry this took so long, but we had to do some digging.

    As for a cylinder sized for 38 special (at 17,600 psi for normal pressure and 19,100 psi for 38 Spl +P), we don't think making one even for 9mm normal pressure is safe (at 36,100 psi) much less 9mm +P (at 39,700 psi).

    I know this isn’t what you wanted to hear, but its safety first at FAMCO Inc.


    Jim Kinkopf