Sig P229 40 to 9mm

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  • Ghost40

    Active Member
    Apr 29, 2015
    216
    Hey all

    Looking for some reliable info on converting my recently (used) purchase of a Sig P229 .40 to a reliable 9mm. Love the gun just not the caliber. Can’t find anything via Sigs site. A few forums online saying just the barrel, need the return spring, need the slide too. In short, a lot of info but nothing seems solid.

    Is there a reliable way to do this or should I sell my red box Sig and get a 9mm.

    Thanks!
     

    Hawkeye

    The Leatherstocking
    Jan 29, 2009
    3,971
    If you want to do it with all SIG parts, you'll need a caliber conversion kit (barrel, recoil assembly, slide, magazines). If you want to do it "aftermarket," you can do it with a Bar-Sto or other conversion barrel, a new recoil spring, and magazines (technically the extractor and breech block face are different also, but some people can get them to run without worrying about that - I wouldn't, but some people do). The reason for this is that the outer diameter of the .40 and .357 barrels is larger than the OD of the 9mm barrels, so the cut in the slide is too large for a factory 9mm barrel.
     

    photoracer

    Competition Shooter
    Oct 22, 2010
    3,318
    West Virginia
    Sig, unlike HK, is not happy doing a barrel only conversion, which is why my SHTF pistols are all HKs with multiple caliber barrels. When you put a 9mm conversion barrel in an HK USP it says you "might have an issue" using 9mm in .40/357Sig mags but Sig says you have to use 9mm mags. That's one reason why I don't have my old P229 Sport anymore and why I kept my HK USP Compact.
     

    K-Romulus

    Suburban Commando
    Mar 15, 2007
    2,427
    NE MoCO
    The conversion kit may/may not work, depending on how old your SiG is.

    I have an older yr 2002 P229r that I converted into a Franken-SiG M11-A1 using a P228 stamped slide, barrel, and 9mm locking block.

    Newer Sigs use the Xchange kits with a universal locking block that doesn’t need switching.

    If you search around Sigforum.com you should be able to find the details of the locking block swap. I got my locking block from Numrich back in 2010 or so.

    Edit: Sig switched its P229 pistol line around 2010 to all use the .40 frames. These 9mm are model “P229-1.” The magwell is larger in the .40 frames. Folks say older 9mm mags worked fine in the frames. Sig made a new line of fatter magazines with the designation “P229-1 9mm.” I have fired a few thousand rounds out of my Frankenstein M11A1 with that setup with no issues.

    P226 is easier - even the pre-2010 models just need a swap of slides and barrels to go from .40 to 9mm (yes I did that, too). Same for P239 (if you can find one).


    Sent from my iPhone using Tapatalk
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,734
    Socialist State of Maryland
    Barsto makes one of the best barrels for the 229 40-9 conversion. Most of my Sig 40 mags worked good with 9mm except for RP. RP have rounded case heads and they didn't work well with the .40 cal mags.
     

    Clem

    Member
    Mar 19, 2007
    99
    Southern MD
    I bought a used 229 in .40 and went with the SIG exchange kit with 9mm barrel and slide to make the conversion. Works great. .40 is ok, but much more expensive to shoot on the range. Just for fun, I got a .357 SIG barrel for it. That stuff shoots like a laser, more accurate than either the .40 or 9mm.
     

    Racer Doug14

    Thread killer
    MDS Supporter
    Patriot Picket
    Feb 22, 2013
    8,003
    Millers Maryland
    I called Sig CS for the same info. I have a W.German made 229r frame. The X-change kit should be ok. But the locking block might be a no go. 229-1 barrels are different. That's what is in the kit. Sig CS was not helpful in clarifying that at all. I'm learning about this and could be wrong.

    I think the confusion is going from 9mm to 40/357. Older non -1 frames won't take the mags. The changeover in 2010-2012 really screw people up. Now, people are dropping out of 40cal and trying to use the flexibility sig touted.
     

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