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.357 Sig bullets?

Discussion in 'Reloading' started by Bluescot, Mar 23, 2013.

  1. Bluescot


    Apr 11, 2012
    I was lining up some 9mm brass to do a run of reloading for them and remembered that I didn't think I had much in the way of bullets for the 9mm.

    I looked in the closet and found some Speer Gold Dot 9mm 115g .355 boxes and also a Speer Gold Dot 357 Sig 125g. .355 box #3994. I bought that box as I had a Sig P226 with both the 40S&W barrel and the .357 Sig barrel but after shooting the .357 Sig about 25 times with factory ammo I put the 40 barrel in and never took it out. Forgot about the 357 Sig bullets

    Question: Why the 357Sig designation on a .355 bullet? Marketing ??
  2. jeffreybehr

    jeffreybehr Silver Member

    Mar 14, 2009
    Phoenix, AZ USA
    I read 2 question there.
    1. The 357SIG uses bullets that are the same diameter as 9mm bullets--0.355" or 0.3555". It does NOT use 0.357"-diameter bullets, and that's why it's incorrect to label it .357SIG as some do. (I tell people that the 357SIG cartridge could have been correctly named the 9mm SuperMag.)

    2. Speer labeled that 125g. bullet for the 357SIG because it's the 6-petal version that's built for the higher velocity of the 357SIG...I believe.

  3. hogfish

    hogfish Señor Member

    Aug 4, 2005
    IIRC, the difference is in the ogive(?) The full diameter must run further out on the SIG than on the 9mm, otherwise the mouth on the SIG will sit beyond the beginning of the ogive (smaller diameter of bullet). Hope I was clear enough. :)
  4. Three-Five-Seven

    Three-Five-Seven Señor Mombo Millennium Member

    Aug 8, 1999
    Great Southwest
    357 sig uses truncated cone profile in order to give more surface area for crimps. The round is notorious for having a very short neck. Standard ogive 9mm bullets will not work in the sig round. I presume the bullets are labeled this way as a service to reloaders.
  5. dougader


    Apr 17, 2004
    Both reasons... it's built for more velocity and greater "shank" length, surface area, ogive... to give a better hold on the bullet with that short 9mm Sig magnum neck....