I just wanted to thank the SF members that clued me in on how easy it was to convert a Sig P239 .357/.40 S&W to 9mm! I bought my P239 used in .357 Sig when I saw it offered for a good price at my LGS. I couldn't carry it in that caliber as my department the .357 Sig, but knew that I'd only have to buy a .40 S&W barrel and magazines to convert it to a caliber which was approved.

That was about ten years ago. Although I didn't carry the piece (as a .40 S&W) very often, when I learned from fellow SF members here that these were easily converted to 9mm, I recently acquired factory 9mm barrel, and bought a 9mm recoil spring so I'd have that option too. Last week, I tried shooting a variety of factory 124 and 147 grain loads through the pistol using both .357 Sig and .40 S&W magazines. Not only did the pistol function perfectly (about 100 rounds through it), but it actually shot noticeably better than with the other calibers!

I like the idea of having the flexibility of converting to another caliber when the need arises and am grateful that informed SF members passed the information on to myself and others that didn't know this was such an easy option with the P239!

So just a barrel and recoil spring and mags?

quote:

Originally posted by ruger357:
So just a barrel and recoil spring and mags?

I only needed the 9mm barrel and recoil spring. As noted by our fellow SF members, the .357 Sig and .40 S&W magazines worked just fine with 9mm ammunition in my P239! YMMV!

Interesting. Most guns need a conversion barrel. Just dropping in a factory barrel usually doesn't work with the extractor and ejector.

Only thing I change is the barrel. No problems.

However, if you don't have a good grip, I suggest changing the recoil spring. As I've saw problems when fired by someone with a weak grip.

And THIS is why one always wants to purchase the .40 S&W version of any Sig...caliber change to 357SIG or 9mm is a barrel, recoil spring, and appropriate magazine.

Same applies to Glocks. Never buy a G19, buy the G23, or the G22 over the G17, etc.

The difference in rim size between the 9mm and .40 S&W is .030", which means .015" RADIUS or just under .4mm...that's 4/10ths of a single millimeter! This difference is well covered by the extractor's ability to grip the rim!

The P239 is an anomaly. A number of SF members have converted their .40 to 9mm using just a Sig OEM native 9mm barrel. GaryBF was one of the early adopters. My own P239 .40 experience:

1) Replace .40 OEM barrel with 9 mm Sig OEM barrel. NOT a conversion barrel, just a native OEM 9mm. Other Sig .40-9mm conversions require a CONVERSION barrel. Possible exception is P226 noted below.

2) Reliable with both .40 and 9mm mags.

3) Had Sig "Plus 1" kit installed on both .40 and 9mm mags. No longer available. It was recommended for use on .40 mags only. Didn't matter, it worked on both.

4) I use the .40 recoil spring with no problems.

The P239 is an anomaly because you can do everything "wrong" and it comes out right.

Somebody will inevitably post that "conversions" shouldn't be used as serious defensive guns. I never got the point. If the damn thing is 100% reliable...it's 100% reliable. So what if it's a conversion? How many instances have we seen where unmodified pistols were unreliable? If it works...it works.

I've heard that the P226 can also be converted in the same manner. Haven't seen a lot of posts on that though.

And the SP2340/SP2022 357/40 SIGPros.

quote:

And THIS is why one always wants to purchase the .40 S&W version of any Sig...caliber change to 357SIG or 9mm is a barrel, recoil spring, and appropriate magazine.

Actually, to get to 9mm this is really only the case for the SIG Pro and P239, I believe all the others require a conversion barrel at a minimum... Extraction isn't usually the problem, in many cases it is the locking insert as well.

Now I'm looking for a 9mm barrel. Thanks a lot!

I notice top gun supply says the 9mm barrel is not for use in the .40 or .357 slide. Any reason?

quote:

Originally posted by ruger357:
I notice top gun supply says the 9mm barrel is not for use in the .40 or .357 slide. Any reason?

Because Sig doesn't sanction this. The 9mm barrel wasn't designed to work in the larger caliber slides. In many (most?) cases it works but if you damage the pistol or hurt yourself you're on your own. Sig also doesn't sanction using .40 caliber magazines for all three calibers but that seems to work as well.

Can anyone speak to their experience with running a 9mm barrel in their 40SW Sig Pro? I'd love to get a barrel for my 2340.

quote:

Originally posted by Peanut71:
Can anyone speak to their experience with running a 9mm barrel in their 40SW Sig Pro? I'd love to get a barrel for my 2340.

Yes. I did it and it worked (sample size of one).

https://sigforum.com/eve/forums...0601935/m/5960010824