357 sig vs. .40 S&W

Discussion in 'Ammunition & Reloading' started by Gordo323, May 12, 2010.

  1. Gordo323

    Gordo323 New Member

    Didn't know where to go to post this question, so here it is as I reload both calibers:
    I have 3 Sig P-226s two in .40 and 1 in .357 sig, I have 15 magazines which all accept .357 or .40 and all fit in every gun.
    I'm sure a .40S&W would not chamber into a .357 sig, but would it work the other way around ? And what kind of bad things would happen?
    Just curious if anyone has made this mistake!
  2. palabman

    palabman New Member

    I'm sure that the case would split at the neck and your accuracy would be terrible. Probably sound kinda funky, but I'm not sure it would damage the gun.

  3. Tackleberry1

    Tackleberry1 New Member

    My son once mistakenly loaded a .45 ACP mag w/.40 S&W, loaded it into my Colt 1991 A1, and pulled the trigger.

    Made a funny noise, like the shot was muffled and split the case leaving it stuck in the chamber. Had to tap it out w/a cleaning rod.

    Did not hurt the gun but I can't say the same for his pride.

    I think your hypothetical would have a similar rusult.
  4. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

    Because the bullet would not attain a good seal inthe barrel, most of the pressure would be directed past the bullet. The case neck would expand in an attempt to fill the vacant space and may split.

    You would not have dangerous pressures by any stretch of the imagination. You would likely have a fail to extract, but otherwise would not be "dangerous".