A buddy of mine found a P239 in 40 and was asking me about a cal change to 9mm and possibly 357Sig. I know that both are possible, but not sure about the mags that come with it. They are labeled as 40S&W. Not 40S&W/357Sig. So do they work with 357 and 9? Also with the sights what changes in POI is he going to see with it? He is probably going to do it since it is $400 and very likely less going out the door. BTW I have seen it and it looks very nice. Just the start of the smiley on the barrel and the rest of the gun looks like new to me. Also he is probably going to carry it. He wants one after shooting mine in 9mm and is going to use it for carry.

It’s generally agreed that 357 SIG ammunition works fine in P239 magazines labeled 40 S&W, but the opposite is not true: Only 357 ammunition can be loaded in magazines so marked.

My understanding is that to use .357 Sig in a P239 .40, both a .357 Sig barrel and .357 mags must be used. The P239 is the only Sig classic P-series that does not have a common .40/.357 mag.

Many, including myself, have found the following to work with a P239 .40:

1) A Sig OEM 9 mm barrel can be used. This is a native 9 mm barrel...NOT a "conversion" barrel. Sig has no position on this, but it does work reliably. It is the only classic P-series .40 that does not need a true conversion barrel.

2) Sig 9 mm mags can be used. They are slightly narrower than .40 work mags and may rattle slightly, but workjust fine.

3) I also use my .40 mags with 9 mm. They also are reliable. Go figure.

4) You can use the Sig "Plus 1" mag kit on the .40 and 9 mm mags. Both are reliable with either caliber. Again, note that Sig recommends the kit only for the .40. No idea why they don't include the 9 mm mags. They will work on the 9 mm.

Basically, I have done everything not officially recommended for the P239. All I know is it still works.

357 sig barrel is a direct drop-in for the 40. I load 357 sig ammo in my 40 mags and I've never had a FTF, or any other malfunction, when shooting 357 sig in my P239. If I were carrying the gun I would probably think twice about using 40 mags as I assume the engineers have a good reason for not having a combined 40/357 sig magazine, but for range use I would give it a try. If he likes it- buy a few 357 sig mags and move on down the road.

No sight change is necessary at combat distances; only 25 yards and beyond.

Adding to the previous replies, if he does decide to buy 357 mags, 9mm rounds shoot well in those too.

Thanks guys! I know he is going to ask me this so what kind of POI changes would he see at 25yds with the 357 and 9?

If he decides to not purchase it, I just might. Always wanted one in 357, but never found one.

quote:

....what kind of POI changes would he see at 25yds with the 357 and 9?

Approximately two inches low.

Thanks.

BTW I think $400 for it is a pretty good deal since it is in very good condition. But what do you guys think?

quote:

Originally posted by Sparkyk:
Thanks.

BTW I think $400 for it is a pretty good deal since it is in very good condition. But what do you guys think?

That's a good deal. That's what I paid for mine about 2 years ago when everyone started dumping .40.

I'd buy it.

Despite some folks gripes about mag capacity and weight, I think it's one of the best CC guns out there. Mine shoots as well as my larger Sigs and carries very well. The fairly inexpensive versatility with the 9 mm config is a bonus.

It disappears in my Sparks VM-2 IWB along with my two mag carriers. Besides the gun, single stacks on the belt are far less bulky than doubles.

To all those who responded and helped me out. Thank you!