I have a Sig 239 that was a police surplus in .40. It is lightly used, has been refinished in two tone brushed nickle and traditional blue crekote finish. I'd like to convert it to 9mm. Is that possible? Thanks.

Yes. A number of us on the SF (including me) have successfully done it. GaryBF was one of the first.

1) Can use a Sig OEM 9mm barrel, unlike most other .40-9mm conversions. No conversion barrel needed, although you could use one.

2) My own P239 .40 to nine "conversion" functions fine with BOTH .40 mags and 9mm mags. Note that the mag well is narrower on the .40 compared to the nine. CORRECTION: Per GaryBF, should read " Note that the mag well is narrower on the nine compared to the .40."

3) Some have changed to 9mm RS, I didn't. Works fine with .40 RS.

4) All my P239 mags have the discontinued Sig "Plus 1" base plates. Function fine with the conversion.

The P239 is somewhat of an anomaly in this regard. If it works...it works.

If the pistol is intended for SD, thoroughly test with your carry loads. Regardless of whether you use a native 9mm barrel or a conversion barrel.

This message has been edited. Last edited by: Nipper,

Thank you so much for the input.
However, due to fat thumbs and poor proofreading, I asked the wrong question. Same question different gun.
Can I convert a Sig P229 in .40 S&W, into a 9mm?
Thank you.

quote:

Note that the mag well is narrower on the .40 compared to the nine.

Nipper, no, it is just the opposite. 9mm magazines are slightly loose in the 40 frame.

Thanks Gary. Same problem as chuck416.

OP, P229 requires a TRUE conversion barrel from Bar-Sto or EFK Fire Dragon. Sometimes the .40 mags will work with 9mm. Try them first. Seems the .40 RS works most of the time. Reliability seems to depend on the specific gun. Coin flip.

https://www.barsto.com/categor...in.cfm?ID=229&cco=68

https://efkfiredragon.com/sig-sauer2.html

Might want to correct the thread title too.

quote:

Can I convert a Sig P229 in .40 S&W, into a 9mm?

Yes, but it is not as easy. Since the P229 uses different locking inserts for the 9mm and 357/40, you must buy a conversion barrel, or find a 9mm locking insert to use with the factory 9mm barrel. As with the P239, the frame are slightly different, so 9mm magazines are loose in the 40 frame, but they work. You can feed 9mm rounds from a 40 magazine or buy P229-1 9mm magazines, which are are slightly wider.

The barrel diameter is different on a .40 barrel than a 9mm barrel, so a barrel, slide, and locking insert are required to use OEM parts to convert from .40 to 9mm on a P229 or the barrel will be lose in the slide at the muzzle end.

.40 barrel OD .545"

9mm barrel OD .525"

The answer is to use a conversion barrel.

It's not the right way to go, but I have shot 9mm with a stock 9mm barrel in the .40 P229 and P226, using .40 mags. It ran fine, but I wouldn't ever carry that or do any real shooting with it. It was a curiosity, and it worked. I imagine it would lead to increased wear.

Inexpensive 40 S&W ammo is available, from police trade-ins. You may find it more advantageous to search for low cost ammo than to convert to 9.

quote:

Originally posted by chuck416:
I have a Sig 239 that was a police surplus in .40. It is lightly used, has been refinished in two tone brushed nickle and traditional blue crekote finish. I'd like to convert it to 9mm. Is that possible? Thanks.

Do you reload? Get a stock 357 sig barrel. I have a barsto 9mm barrel for my 229 but seldom use it as have 226 in 9mm. One can reload 357 sig for slightly more than for 9mm once have enough 357 sig brass on hand. I like starline. You can use your 40 cal mags.